WiX Layering Improvements

[wixbot]

This proposal suggest breaking the single wix.dll into three assemblies and layering the programmatic surface area of the WiX toolset as follows:

1. data - WixToolset.Data.dll
2. extensibility - WixToolset.Extensibility.dll
3. processes - wix.dll

The layers will reduce the programming surface area to the necessary subset for WiX extension developers and better formalize the interfaces WiX developers should keep in mind when making changes.

Originally opened by firegiantco