Transcribe AP-REP and EncAPRepPart

GSS-API with mutual authentication will need it.
Some flags and documentation for options
More GSS-API stub stuff

I should just sit down and implement this thing.
Rename krb.js to krb_proto.js

krb.js will hold things like KDC.Principal and friends. Issue #38.
Move KDC.{Principal,Key,realm} to krb namespace

So that kdc.js can be limited to the UI code. Issue #38.
Move KDC.Session to krb.Session

Closes #38.
Formatting
Some extra renames
Move kdc.js to webathena-ui.js

This makes webathena.js somewhat more generally usable. Although it's
pretty heavy. This is possibly not the might reasonable way to go about
that. Not sure.

Keeping issue #18 open, but it's relevant.