Documentation Overhaul

This is a major overhaul of the documentation for grunt-ts.  There is still some more cleanup to do and it could use more cross-referencing hyperlinks, but I think this came out pretty good.

The new documentation attempts to make it super easy to get started and provides more commentary for all currently working `gruntfile.js` options.

I can keep working on this further if people have comments.

You can see the new docs fully rendered here:

https://github.com/nycdotnet/grunt-ts/blob/Docs-Overhaul-2014-12-04/README.md