Removed githubi function.

- Not really needed with Git 2.x.
Fixed tfollowers function so that it exits early when CLI commands are
not found.
Updated tfollowers function to use Dropbox cache instead of home dir.
Refactored private _clip_and_print function to _copy_and_print.
Added "ghd" function for deletion of git hooks for current project.

- Only deletes hooks for current project AND only if .git dir is
  found.
- WARNING: Does not prompt for confirmation.
Added "ghda" function for deletion of Git hooks for all projects in
currenct directory.

- WARNING: Does not prompt for confirmation.
Fixed "gia" function so Git hooks are actually initialized for all
projects.