Fixed comments that were inconsistent with the style guidelines described in C++ core guidelines and the modern C++/WinRT language projections and removed trailing whitespace.
Inserted a space after the beginning of the comment so the text wasn't touching the // on all occurrences.
Removed all occurrences of trailing whitespace
A few small changes to improve the view of the code in Solution Explorer:
* Delete folders from solution explorer which don't appear on disk (Resource Files, PerfTrack)
* Delete files on disk which aren't compiled into the project (Type.xaml)
* Rename CalculatorHistory.Cpp to CalculatorHistory.cpp, for consistency with other files
