doc: remove unsued progs and makehtml script, update progs/run

doc: remove unsued progs and makehtml script, update progs/run
        Due to removal of go_tutorial, unused programs are removed.
        makehtml is unnecessary (it also gives wrong messages when
        the destination file doesn't exist)
        progs/run now compiles all remaining programs under doc/progs.
        Fixes #3076 (again)

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/5755053