Added support for multiple authors within commit
Removed some unneeded pyc files
fix some bug in branch_list and download_and_process_all_branches
add additions and deletions to CodeAuthor
commit migration for additions and deletions
Merge remote-tracking branch 'remotes/origin/master' into add_all_branches
commit the (missing) migration for additions and deletions. additions and deletions are now compatible with multiple authors.