This is Go 1 package renaming CL #2.
This one merely moves the source; the import strings will be
changed after the next weekly release.

exp/template/html -> html/template
big -> math/big
cmath -> math/cmplx
rand -> math/rand
syslog -> log/syslog

The only edits are in Makefiles and deps.bash.

Note that this CL moves exp/template/html out of exp. I decided
to do that so all the renamings can be done together, even though
the API (and that of template, for that matter) is still fluid.

R=r, rsc
CC=golang-dev
https://golang.org/cl/5332053