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
SublimeText projects are often user edited so I think pretty printing is necessary. Main use case I can think of is adding a custom build tool with some additional defines etc.