Add a VS_DEPLOYMENT_LOCATION source file property to specify where to
put files that are part of the package. For example:
set_property(SOURCE ${ASSET_FILES} PROPERTY VS_DEPLOYMENT_LOCATION "assets")
Without this, sources marked with VS_DEPLOYMENT_CONTENT cannot be
located properly.
Create properties VS_SHADER_ENTRYPOINT and VS_SHADER_MODEL. Without
these many .hlsl source files may not be possible to use. Extend the
VSWinStorePhone test project to cover them.
