Add iter_* functions to repos.py and fix bugs found while doing that
Add iter_* functions to repos.py and fix bugs found while doing that

- Remove 'paginate?' comments as this can now be done by iter_*
- list_commit didn't use its params
- Branch, RepoCommit and RepoComment had broken __repr__'s

icio/github3.py,krxsky/github3.py,h4ck3rm1k3/github3.py,degustaf/github3.py,agamdua/github3.py,ueg1990/github3.py,balloob/github3.py,sigmavirus24/github3.py,jim-minter/github3.py,wbrefvem/github3.py,itsmemattchung/github3.py,christophelec/github3.py