Cosmetic
Modifications required to support commit ids with strings instead of revisions with int
Initial work on issue #6 , still more to do on this since I don't know how to handle these issues:
 * Merge conflicts
 * Revisions in SVN were represented as int, so it was easier to do things like max(rev1, rev2) and easier for the user to understand that he was updating from revision 123 to 125 instead from long_hash1 to long_hash2