Enhanced AppleScript support

Added enhanced AppleScript syntax parsing, and an AppleScript theme that closely mimics the OS X AppleScript Editor's aesthetic:

![Screen Shot 2013-02-22 at 10 53 25 PM](https://f.cloud.github.com/assets/1349578/187578/9cd24f14-7d6c-11e2-9e73-06e5a87b69ca.png)