wish: documented supported Go versions

[markstos]

For this who wish to compile, it would be useful to document the versions of Go that it has been tested with or it is expected to work with.

[markstos]

I tested compiling with go 1.2.1 and gccgo 4.9.1, and that worked fine.

The one problem I had is that it compiled so fast, I didn't think anything could have possibly happened.