Switched Bazaar support from checkouts to branches for easier updates. Added support for bzr+sftp and fixed bzr+ssh transport.

Made freeze and bundle command use the version control system registry instead of explicitely calling the backends.

Redid the registratio system for the version control support. Added schemes attributes to version control classes. Fixed some minor bugs. Added Bazaar version control class.

Fixed some cosmetic issues.
Simplified Git support a bit.

[svn r21811] Don't use sys.exit directly.  Put install record in .egg-info/ directory.  Add --simulate and --path to pip zip