Added basic 'Run' command

Hello! 

Here is a basic 'Run' command classic 'Cmd + R' 

- I should have implemented the Regexps for parsing and correctly formatting the errors in the  TextMate output dialog when errors occur. Working on that :) 
- When the file has still not been saved TextMate will ask to save it before running I've added the call to TextMate function

```ruby
TextMate.save_if_untitled('exs')
```
But for some reason Textmate is putting and 'ex' extension instead of the 'exs' probably a bug in TextMate support libraries. Working on that to :) 

But now you hit Cmd + R and there you go!