Set up Godoc

[dadrian]

There's some way to autogenerate documentation from comments. The original Google code already has the comments, so at the very least that would autogenerate. We should generate it, and modify it according to our changes.

[dadrian]

http://godoc.org/github.com/zmap/zcrypto

[dadrian]

We should read through the documentation, and update information about the forks, and write intro doc.go pages for everything.