Add an alias for a matrix map.
Create a templated method in the MeshModel and IOMesh to automatically
cast the underlying mesh.

Create an interpolate() method in the VegaVolumetricMesh class to
interpolate surface of the underlying volumetric mesh with an external
surface mesh and clean up the interface.

Create a computeGravity() method in the VegaVolumetricMesh class
to compute gravity forces.

Refactor getVelocity() method in DeformableSceneObject and add a
variable to hold the gravity vector.

Refactor SceneObject. Add SceneModelRenderDelegate render delegate to
take care of renderign operations for this model. Create visual,
physics and collision model variables.

Remove render delegates from the StaticSceneObject, this is now handled
by it base class.

Add storage for the gravity force in VegaFEMDeformableSceneObject and
initialized properly. Compute internal force by multiplying K*positions
instead of calling the vega function.

Refactor DefaultSimulator, VegaFEMModelSimulator. This class will be
marked obsolete soon.

initialized from Vega matrices. The ode rhs
now considers damping only if the coefficients are
positive, non zero. It also accumulates contact forces
if any. The updateAttachedMesh in the VegaVolumetricMesh
class now takes an Eigen vector to do the update.

for surface meshes. This was causing crashes when trying to
render. Clean the attachSurfaceMesh routines and add two more
routines: readWeigths() and generateWeigths().

Automating the way renderers are loaded.

Fix broken tests.
The renderCube example is broken now. Submitting patch soon.

Revert to build command in the Superbuild so that parallel
build work again.

Clean up and add static scene delegate.

Documenting IO. Change name for IO delegates to match file name.

Capture by value in the IO delegator so that it remembers about the
delegate file name and IO pointer.

Fixing examples so they use the new IOs and renderer.

Add tests to IO. Move variables, types and implementation
of utility methods to IOMeshDelagates base class.

Commented out the VegaVoumetricMesh test until after I debug the meshIO.

Add reset function to base mash

in order to reset vertices to their original position.
Strip const from read function in the IOMeshDelegate and childs.
Move some utility functions to IOMeshDelegate.

Also renmamed many unseen sm* class names.

Also fix instances where normalized was used wrongly.
Thank @tansel for spoting these.

Issue #27