ST3 fixes and optional Tab Context Menu

@bizoo I've been playing with your plugin a bit more, and I noticed there were some more ST3 fixes that needed addressing.

Also, I have been on a menu kick, and I added an optional Tab Context Menu option.  If you don't want the menu, you can pass on the last commit.

![screen shot 2013-12-28 at 9 45 04 am](https://f.cloud.github.com/assets/1055125/1818104/99b080a6-6fdf-11e3-9f02-6e40f12e6610.png)