Added OSDetection.c
Added OSDetection.c

This file determines the operating system the current instance of the adventure
engine is running on.

DrItanium/electron-platform,DrItanium/electron,DrItanium/electron,DrItanium/AdventureEngine,DrItanium/neutron,DrItanium/electron-platform,DrItanium/AdventureEngine,DrItanium/electron,DrItanium/electron-platform