Pulling in FSharp Depth colorizer.
Made the depth colorizer work with the FSharp Compiler Services.  This is not integrated with the rest of the PowerTools.
Removed additional unused files.
Move the code to a single project

Make it work with VS 2013
Integrate FSharpDepthColorizer with other projects
Port service registration to C#

The problems still persist:
- The extension doesn't load in VS2012
- It is fragile in VS2013
Added tests and docs for depth colorizer
Added new set of default colors to depth colorizer

As well as the original default grey scale have added another set that
will be used when a dark theme is in use
Merge pull request #75 from ChrisDobby/depth-colorizer

Depth colorizer tests, docs and change to default colors
Reuse InteractiveChecker instances in Depth Colorizer feature
Show depth colors before text markers in order to avoid conflicts with highlighting references
Merge branch 'depth-colorizer'
Move XmlDoc and DepthColorizer to Core and Logic as other features