Projection of CanvasImageBrush.
Bugfix: didn't build if there were spaces in the enlistment directory name
Fix Visual Studio version detection in build.cmd
Updated README.md and CONTRIBUTING.md
- Renamed CONTRIBUTING to CONTRIBUTING.md
- Moved directory structure info from README.md to CONTRIBUTING.md
- Updated contribution process
  - CLA submission process now automated via the Azure pull request bot
  - Detailed the contribution process including How-To for verifying changes
Delete unused CppConsumer project.

This fixes a bug where Visual Studio would hang after opening Win2D.sln if there
was not already a Win2D.suo file.  Not sure why (still working on that) but CppConsumer
was an empty stub in any case, so we may as well just delete it.
Add CanvasBitmap.Bounds property