clone does work on all branches.

defect:
- repo not shown in the user's list
- clone default branch twice
Fix warning related to naive datetime
Add all branches is now working using download_and_process_repo_all_branches()
Other branches now inherit names and description from the default branch
Merge remote-tracking branch 'remotes/origin/master' into add_all_branches
update update_repo() to support branches
Add branch_list to GitStore