add script to open iTerm rather than Terminal
update terminal.osa to use iTerm if available

remove my separate iTerm.osa and use [Dan's changes](https://github.com/zaggino/brackets-git/pull/762)
Merge remote-tracking branch 'upstream/master'
show git status when opening terminal
fix test for iTerm

fixes zaggino/brackets-git#788
use native AppleScript rather than shell script to osascript
Merge pull request #801 from macbookandrew/master

fixes iTerm test