add incremental mass recalculation
fix windows build - also broken in master
camelcase
fixed diagonal splitting, my bad.
Merge pull request #155 from voxelinc/incremental_mass_calculation

add incremental mass recalculation
Merge branch 'master' of https://github.com/voxelinc/voxellancer into recalculate_voxeltree_and_aabb_after_split

Conflicts:
	src/physics/physics.cpp