[cctbxbb] updated project docs

[Nathaniel Echols]

FYI, I finally updated the online documentation for the first time
since switching the project backend.  Included in this is the
corrected link for the SVN browser, which for the record is now:

http://sourceforge.net/p/cctbx/code/HEAD/tree/trunk/

(I find this somewhat over-engineered, but the old URL only shows the
frozen repository as of early March, so we don't have a choice.)

If anyone notices broken stuff, please let me know.

-Nat