Add OsgSkeletonRepresentation to render rigged meshes.

- The mesh is made of bones and triangles lists.
- Setting the pose of the bone moves the connected triangles.
- Each vertex may be influced by more than one bone.
Merge branch 'feature/skeleton-rep-base' into feature/skeleton-rep
Fix Linux errors and warnings.

- Removed forward declarations on the header file and instead included appropriate osg headers.
- Removed repeated "callback =".
Use single RigTransformHardware + Add bone translation + Minor changes

- Rename m_root to m_rootTransform in BoneMapCreator
- Fix Linux errors
- Updated UnitTests
Add Gauss-Legendre 2D 3-points integration (for quadratic fnc over triangle)
(Math) Make all Gauss quadrature arrays const.
Merge branch 'feature/3PtsGaussIntegrationIn2D' into 'master'

Add a 3 points Gauss integration rule for integration over triangle

Merged-on: https://www.assembla.com/code/OpenSurgSim/git/merge_requests/1243273
Order includes according to OSS code standards.
Merge branch 'feature/skeleton-rep' into 'feature/skeleton-rep-base'

Add OsgSkeletonRepresentation to render rigged meshes.

Merged-on: https://www.assembla.com/code/OpenSurgSim/git/merge_requests/1224393
Merge branch 'feature/skeleton-rep-base' into 'master'

Add OsgSkeletonRepresentation to render rigged meshes.

Merged-on: https://www.assembla.com/code/OpenSurgSim/git/merge_requests/1245753