Implement structure definition in data files. Add some data files
Merge branch 'master' of github.com:mathkr/LD31

Conflicts:
	src/test/World.java
	src/test/structures/CopperMill.java
	src/test/structures/CopperMine.java
	src/test/structures/GlassMine.java
	src/test/structures/PSU_T1.java
	src/test/structures/SilverMine.java