MSVC: change "/W2" to "/W3 /wdxxxx..."

[flichtenheld]

When switching to CMake we lowered the warning level for MSVC build from /W3 to /W2 to be able to enable /WX (i.e. treat warnings as errors). Probably there are only very few warning classes that prevent us from using /W3 (which is MSVC default). Check which those are to ignore less warnings.

[jneimanlegal]

2C+6Y=BINARY 0.0110 #450