Encoder now writes tRNS chunk for non-opaque paletted images.
CL includes new test images (basn3a08-trns.[ps]ng).

R=nigeltao, rsc, r
CC=golang-dev
https://golang.org/cl/4432078

R=rsc, bradfitz
CC=golang-dev
https://golang.org/cl/4436074

On my laptop, I had an 800x600 jpeg and an 800x600 png (with
transparency). I timed how long it took to draw each image onto an
equivalently sized, zeroed RGBA image.

Previously, the jpeg took 75ms and the png took 70ms, going through
the medium-fast path, i.e. func drawRGBA in draw.go.

After this CL, the jpeg took 14ms, and the png took 21ms with the
Over operator and 12ms with the Src operator.

It's only a rough estimate basd on one image file, but it should
give an idea of the order of magnitude of improvement.

R=rsc, r
CC=adg, golang-dev
https://golang.org/cl/4468044

R=adg
CC=golang-dev
https://golang.org/cl/4468043

R=adg
CC=golang-dev
https://golang.org/cl/4471041

R=rsc
CC=golang-dev
https://golang.org/cl/4463042

R=golang-dev, bradfitzwork
CC=golang-dev
https://golang.org/cl/4466041

The file is called gotest.exe now.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/4444090

Should prevent failures on slow machines, such as:
http://godashboard.appspot.com/log/47b5cae591b7ad8908704e327f3b9b41945d7d5fecfc0c8c945d5545ece1a813

Verified the change (on a fast machine) by removing the
existing sleep, in which case the race happens ~50% of the
time with GOMAXPROCS > 1, but recovers gracefully with
retries.

R=rsc
CC=golang-dev
https://golang.org/cl/4441089

R=r
CC=golang-dev
https://golang.org/cl/4431088

R=r, r2
CC=golang-dev
https://golang.org/cl/4435083

R=golang-dev, r, adg, r2
CC=golang-dev
https://golang.org/cl/4457049

R=iant, iant2
CC=golang-dev
https://golang.org/cl/4453058

Note that if you are working on the upcoming release
branch you have to point your extension path to a
copy of lib/codereview/codereview.py that won't change
as the repository flips between release-branch and default branch.
This warning should only apply to this one branch and only to rsc,
but you never know.

R=adg
CC=golang-dev
https://golang.org/cl/4446076

Fixes #1748.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/4444087

Fixes #1350

R=rsc, bradfitzwork
CC=golang-dev
https://golang.org/cl/4432089

Fixes #1771.

R=adg, rsc1
CC=golang-dev
https://golang.org/cl/4437089

$ file $GOROOT/bin/{godoc,goyacc}
/home/rsc/g/go/bin/godoc:  ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), not strpped
/home/rsc/g/go/bin/goyacc: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, not stripped
$

Fixes #1758.

R=iant
CC=golang-dev
https://golang.org/cl/4428079

R=rsc
CC=golang-dev
https://golang.org/cl/4435081

R=rsc
CC=golang-dev
https://golang.org/cl/4426077

Fixes a JS crash which prevented the automatically generated
table of contents to not appear.

R=adg, bradfitz
CC=golang-dev
https://golang.org/cl/4460041

Fixes #1764.

R=rsc, r, iant, ken2
CC=golang-dev
https://golang.org/cl/4431082

accidentally deleted one method
TBR=rsc

R=rsc
CC=golang-dev
https://golang.org/cl/4438090

This speeds up PNG decode about 20% by avoiding per-pixel interface conversions.

R=nigeltao, rsc
CC=golang-dev
https://golang.org/cl/4428080

R=bradfitz
CC=golang-dev
https://golang.org/cl/4430075

If localhost resolves to ::1, the IPv4-only test fails.

R=rsc, r2
CC=golang-dev
https://golang.org/cl/4444084

R=rsc
CC=golang-dev
https://golang.org/cl/4428078

Fixes #1647.

R=adg, rsc1, r2, rsc, r
CC=golang-dev
https://golang.org/cl/4444083

This was seen breaking the slow arm5 builder:
http://godashboard.appspot.com/log/ec54ee302a70c07093e8f5c47454b3eb48768b77e1d8cc7943d8951f8b6696be

The test was unnecessarily complex and didn't benefit from
using httptest.Server. That just got in the way.

R=rsc
CC=golang-dev
https://golang.org/cl/4439088

Fixes #1569

R=rsc, bradfitzwork
CC=golang-dev
https://golang.org/cl/4456045

The new gotest ignores Test functions outside *_test.go files
(the old shell script allowed them), so replace one clumsy hack
with another.

The root problem is that the package makefiles only know
how to run cgo for source files in the package proper, not
for test files.  Making it work for test files is probably more
trouble than it's worth.

R=bradfitz
CC=golang-dev
https://golang.org/cl/4452060

R=rsc
CC=golang-dev
https://golang.org/cl/4439087

- added a cache for last file looked up: avoids binary
  search if the file matches

- don't look up extra line info if not present
  (it is almost never present)

- inline one critical binary search call (inlining
  provides almost 30% improvement in this case)

Together, these changes make the go/printer benchmark
more than twice as fast (53% improvement). gofmt also
sped up by about the same amount.

Also: removed an unused internal field from FileSet.

Measurements (always best of 5 runs):

* original:
  printer.BenchmarkPrint     5    238354200 ns/op (100%)

* using last file cache:
  printer.BenchmarkPrint    10    201796600 ns/op (85%)

* avoiding lookup of extra line info:
  printer.BenchmarkPrint    10    157072700 ns/op (66%)

* inlining a critical binary search call:
  printer.BenchmarkPrint    10    111523500 ns/op (47%)

gofmt (always best of 3 runs):

* before:
  time gofmt -l src misc
  real	0m33.316s
  user	0m31.298s
  sys	0m0.319s

* after:
  time gofmt -l src misc
  real	0m15.889s
  user	0m14.596s
  sys	0m0.224s

R=r, dfc, bradfitz, rsc1
CC=golang-dev
https://golang.org/cl/4433086

No language change.

- added a few examples with parentheses
- added a corresponding sentence to assignments
  (this explicitly permits: (_) = 0, currently allowed by 6g,
  gofmt, but marked as an error by gccgo).

R=rsc, r, iant
CC=golang-dev
https://golang.org/cl/4446071

Uses of $INCLUDE and $NPROC are left over from Plan 9.
Remove them to avoid causing confusion.

R=golang-dev, r2
CC=golang-dev
https://golang.org/cl/4445079

R=rsc, adg
CC=golang-dev
https://golang.org/cl/4426074

Fixes #1694.

R=golang-dev, rsc1, rsc
CC=golang-dev
https://golang.org/cl/4445067

Fixes #1767.

R=rsc
CC=golang-dev
https://golang.org/cl/4436073

Works around bug in kernel implementation on old ARM5 kernels.
Bug was fixed on 26 Nov 2007 (between 2.6.23 and 2.6.24) but
old kernels persist.

Fixes #1750.

R=dfc, golang-dev
CC=golang-dev
https://golang.org/cl/4436072

Avoids image.At(), color.RGBA(), opposing 8 bit shifts,
and min function calls in a loop.  Not as pretty as before,
but the pure version is still there to revert back to
later if/when the compiler gets better.

before (best of 5)
jpeg.BenchmarkEncodeRGBOpaque   50   64781360 ns/op   18.97 MB/s

after (best of 5)
jpeg.BenchmarkEncodeRGBOpaque   50   42044300 ns/op   29.23 MB/s

(benchmarked on an HP z600; 16 core Xeon E5520 @ 2.27Ghz)

R=r, r2, nigeltao
CC=golang-dev
https://golang.org/cl/4433088