irc: Switch to golang.org versions, not google code versions of dependencies

[rburchell]

This has a few advantages:

• the google code versions are no longer maintained
• the google code versions are using mercurial (which I don't have installed)

(NB: please go easy on me. this is the first time I've actually poked a go-using project, so I'm not fully sure what I'm doing yet. Seems to build and runs OK, and I can make and use passwords, but I haven't tested extensively.)

[edmund-huber]

Thanks for the contribution! Here's more background info:

• Go 1.4 Subrepo Renaming
• announcement

Do you mind also fixing the link to http://godoc.org/code.google.com/p/go.crypto in the README.md?

[rburchell]

Done :)

[edmund-huber]

Thanks.