Changed project setup.

Better directory structure. Separated .h and .cpp files. Intermediate files in obj. Executables in bin. All source under source.
Using property sheets.
-- DirectX11_WorkShop_All.props = properties shared by all configurations.
-- DirectX11_WorkShop_Debug.props = properties for debug.
-- DirectX11_WorkShop_Build.props = properties for release.
Changed folder includes to use /, rather than \.