Revert "Fix generating export targets file"

This reverts commit d784683e4131bf3cea28e798d4da4e884f510e55.

It was decided not export OpenSurgSim from the build directory. It will
only be exported when installed. As this is largely not used by other
projects and not well supported.

refs #38
Adds unit tests for PhysicsManagerState.
Add Math::SurfaceMeshShape for rigid body phx (disk, shell, hollow mesh,...)
Removes unnecessary construction in PhysicsManagerStateTests.
TransferInputPoseBehavior::doWakeUp checks for needed representations.
InputComponent requires input device on wakeup.
Log level of critical when failing to connect input component to device.
Adds missing documentation in InputConsumerInterface.h
Add Unit Test for FemElement1DBeam isValidCoordinate/computeCartesianCoordinate
Add Unit Test for FemElement3DTet isValidCoordinate/computeCartesianCoordinate

+ add validity range test in isValidCoordinate (each entry must be in [0 1])
Add doc + made the mesh const + fix typo + add emptyMesh test
Fix broken build, now accessing the Mesh from MeshShape as a const

+ TriangleMesh::getNormal needs to be const, which it should have been in the 1st place.
+ TriangleMeshTriangleMeshDcdContact.cpp cast to access a <const TriangleMesh> now.
Rollback Mesh-based shapes on containing a "const" TriMesh and add documentation

The MeshShape/SurfaceMeshShape will be used for passing DeformableRepresentation from Physics to Collision as well,
so they will have their internal TriMesh updated/changed.

We have 2 case scenario and the documentation specify this difference:
* Rigid => mesh never changes => geometric properties always valid.
* Deformable => mesh changes => geometric properties invalid but the physics does not need them in the deformable case.
Rollback 'const' changes to TriangleMesh/TriangleMeshTriangleMeshDcdContact
Fix include order in InputComponent.
Update algorithm documentation for more clarity
Make SurfaceMeshShape::getMesh a non const method
Change volume unit writing to something more standard
Add documentation about thickness

* constant over the surface
* multiple order of magnitude smaller than the 2 other dimension of the mesh
* no smaller than 1e-5 in practice
Make MeshShape::getMesh a non-const method