Added retrieval of ghost information from map file, map validity checking (WIP) and code optimization
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global.h
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- Increased FPS to 7

characters.h
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- Reduced overhead by passing the Map by reference to all functions
- Ghost
	- Modified isHitByBullet() to clear the death spot on the screen properly
	- Modified spawn coord randomizer to use better random code

game.h
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- Added a way for the program to skip a map if the map file is invalid

maps.h
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- Map
	- Added a bool valid to keep track of map file validity
	- Modified constructor to check if map file is valid before proceeding & if not, set valid to false otherwise true
	- Modified processMap()
		- Added code to retrieve ghost stats from map file
		- Modified code to get number of ghosts from ghost stats instead of the G parameter in the map file

scorePoints.h
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- Added to store globals that control how much score each action in game gives