Added OctreeShape

Added a shape that contains an octree root node.
Added unit tests for OctreeShape

Also added missing <memory> include in OctreeNode.

Added getClassName to OctreeShape, but didn't add serialization.
Removed trailing whitespace from OctreeNode and Geomtry.h

Removed three trailing whitespaces in OctreeNode, Geometry.h and the
GeometryTests.
Add SURGSIM_FAILURE to un-implmented OctreeShape functions

Instead of return 0 values for the OctreeShape functions
(calculateVolume, ...) call a SURGSIM_FAILURE indicating that the
function insn't implemented yet.
Document private members of OctreeNode and OctreeShape
Add test for OctreeShape::getClassName
Merge branch 'feature/octreeshape' into 'master'

OctreeShape

Merged-on: https://www.assembla.com/code/OpenSurgSim/git/merge_requests/595943