Updated Main Menu UI

Added single player button that goes into game and plays a local game,
Join button opens a second menu where address and port can be entered.
Added memcheck

Added to define to enable and disable memcheck
Fixed memory leak
fixed compile error because of project type change
moved the location of memcheck
switched back to win32 app on windows and fixed typo
unmodified memcheck.h
Moved Windows specific code to separate file

added main.cpp and moved windows specific code related to spawning a
WIN32 window to a separate file