Add git-hooks formula

Closes #25.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
New formula: hg-fast-export

Closes #20.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
despotify: update with new upstream and missing dep

Closes #18.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>