Changed RandomAccessIterator to be a proxy to objects rather than pointers

~CHANGE: If a Voxel is split into two Voxels and one of them doesn't
contain any triangles and additionally has a Volume of 0, then the
algorithm terminates.

~CHANGE: Compile with -fpermissive in order to permit template code
 to be type-unchecked

~CHANGE: Temporary change: removed cleanup code from MemoryAllocator as it
 caused a crash. (see NOTE)

NOTE: A lot of memory leaks are produced in the current code.
Merge branch 'fastkdtree-SS13-group1' of https://github.com/happah-graphics/happah into fastkdtree

Conflicts:
	happah/testmain.cpp