Added frustum Culling feature
Mocked up the viewer to get working the CullVisitor in failing tests
Precreate Vec4 arrays in getFrustumPlanes function
Added the possibility to enable/disable frustum culling at node level. Unit testing added.
Added the posibility to fully disable/enable frustum culling at viewer level as an option
Merge pull request #66 from jtorresfabra/frustum_culling

Frustum culling