Added SublimeText Project Generator

- Added generator to create project files for SublimeText
- Adds import folders to the project for navigating etc.
-  Generated project inlcudes build systems to invoke DUB build test or run from inside SublimeText

Usage
dub generate sublimetext
This isn't very useful atm, can you group the paths by dependency names.
![subl](https://cloud.githubusercontent.com/assets/288976/5432470/0195f2ac-843c-11e4-98b8-1acd39114ae7.png)
It should say something like, libevent, dub/source, userman/views etc.