Include windows.h in a single point in the source, so we can be consistent about the definition of UNICODE and have core utility functions for Windows that all modules can share. I think this also fixes the bug relating to non-latin characters in filenames, since UNICODE wasn't defined in SDL_rwops.c

/*
 *	common.h
 *	written by Holmes Futrell
 *	use however you want
 */

#define SCREEN_WIDTH 320
#define SCREEN_HEIGHT 480

extern int randomInt(int min, int max);
extern float randomFloat(float min, float max);
extern void fatalError(const char *string);