buggy version for interiors
final, working version
Merge remote-tracking branch 'origin/interior' into diferentialEquation

Conflicts:
	src/main/java/matrixgeneration/Element.java
	src/main/java/pl/edu/agh/mes/gg/twod/A1.java
	src/test/java/pl/edu/agh/mes/gg/TreeBuilderTest2D.java