Dynamo Addin Generator

This pull request is for the addition of a utility to generate addin files based on the Revit Products and dynamo installs on a user's system at run-time. The DynamoAddinGenerator.exe now runs at the conclusion of the install. It deletes all existing dynamo addins and generates new ones. This pull request also updates the Dynamo install location to <Program Files>\Dynamo 0.7.

The DynamoAddinGenerator.exe and the RevitAddinUtility.dll (2015) are bundled in the installer and will appear in the install's base directory.

The addin should recognize for the following install locations:

C:\Autodesk\Dynamo\Core (0.6.3)
C:\Program Files(x86)\Dynamo071 (0.7.1 - before we fixed the x86 folder issue)
C:\Program Files\Dynamo071 (0.7.1 - after we fixed the x86 issue)
C:\Program Files\Dynamo 0.7 (0.7.x - install location as of this PR)

The generated addin should point to a DynamoRevitVersionSelector.dll in the appropriate Revit_2014 or Revit_2015 subfolder of the Dynamo install. The version selector external application logic is responsible for registering Dynamo installs as buttons in the Revit ribbon.
I would consider changing the usage a little

Default (i.e. no command args) - display a string telling you what the tool does
-displayOnly - Just dumps the Revit and Dynamo products that are installed
-installAddins - Does the required adding writing thing