These are the Go 1.4 docs but refreshed for Go 1.5.
The most sigificant change is that all references to the Plan 9 toolchain are gone.
The tools no longer bear any meaningful resemblance.

Change-Id: I44f5cadb832a982323d7fee0b77673e55d761b35
Reviewed-on: https://go-review.googlesource.com/10298Reviewed-by: Rob Pike <r@golang.org>