Moved most inline HTML to template files
Added Persona login flow to index page
Added login requirement to most actions
Added capability for adding new files
Started cloning to per-user directories
Fixed start point of new branches
Detouring into unit tests since it's getting complicated
Added simple test for starting and saving a branch
Added test for creating a new working files
Added tests for merges and conflicts
Switched to subprocess-style git commands.

Addresses git version incompatibilities, more detail:
* https://github.com/gitpython-developers/GitPython/issues/142
* https://github.com/gitpython-developers/GitPython/pull/143
Added merge from default branch to each save_working_file() call
Rolled upstream branche merges into a loop
Hopefully fixed upstream merge conflict state bugs
Added half-done complete_branch() and tests
Added working branch delete to finish complete_branch()
Started populating commit authors from session email
Started using start_branch() more consistently
Git seems to want non-empty strings for author names
Improved comments and test coverage throughout