Add crawler

[sevko]

Tasks

• [x] Add parent crawler module.
• [x] Add all subsidiary crawler modules.
• [x] Complete crawler package.

  Crawlers

• [x] GitHub
• [x] Bitbucket
• [ ] Gitorious
• [ ] local installs of git repositories
• [ ] Mercurial repositories
• [ ] Subversion repositories
• [ ] Programmer's blogs

[sevko]

Closing, as no more Codelet harvesting capacity is currently necessary.