Hello D3D11 -HelloD3D11.cpp - various

[spec-chum]

• Text says to #include various files, then doesn't include them itself - they're pulled in by other headers, but this is not made clear.
• We're asked to include a template for ComPtr in the .cpp file, however this is already in the .hpp file
• Text uses CreateDXGIFactory2 but code on GitHub uses CreateDXGIFactory1
• The GitHub code doesn't match the text in various places by this point