Some pragma warnings are not more needed for VS2015 compilation this
removes them.
Removing some specific code for older version than VS2015.
Forcing build to fail if compiling with VS older than VS2015.
Differential Revision: https://code.wildfiregames.com/D1396
Reviewed by: @Itms
This was SVN commit r23416.
Throwing exception on NULL is a bit extreme, and unhelpful when it
happens in rarely-tested error paths. Printing "(null)" is safer and
provides compatibility with glibc sprintf.
This was SVN commit r16180.
