"Samples\Content\cpp-win32\Squares\Squares.vcxproj" doesn't configure precompiled headers correctly

[mschofie]

"Samples\Content\cpp-win32\Squares\Squares.vcxproj" doesn't configure precompiled headers correctly, meaning that:

1. 'pch.cpp' is compiled unnecessarily
2. Other '.cpp' files don't benefit from precompiled headers.

Only the Debug|Win32 configuration actually specifies any precompiled header settings, and they appear to be wrong - it sets the PrecompiledHeader metadata to Create for all ClCompile items, it should be set to Use by default and Create for pch.cpp.

Without precompiled headers (i.e. as the project is currently defined) the build takes ~26 seconds on my machine. Opt-ing in to precompiled headers takes it to ~11 seconds for a full build, and incremental builds would also benefit.