added basic level definition

introduced xml file with basic level parameters incl. platform resources
added level data class

incl. parsing and translation into specific data object instances
implemented xml-driven platforms

incl. enum optimization
deleted old code fragments
added xml description for parallax background images
Merge branch 'dev' of https://github.com/davidbeermann/econarchy into dev

Conflicts:
	Econarchy/Game.pde
	Econarchy/Level.pde
	Econarchy/Platform.pde
merge cleanup