New testcases to expose bug.

- Added convenience member function to Triangle class.
- Added new test cases that exposes a bug in
  calculateContactTriangleTriangle.
Added special cases to be handled in contact calculation.

- Modified calculateContactTriangleTriangle to handle special cases where
  the penetration depth is determined.
- Refactored code after adding special cases to be more readable.
cpplint fixes.

- Some lines were more than 120 characters.
- Some lines had blank tabs.
Updated testcases for TriangleMesh/TriangleMesh DcdContact.

- A mesh with 99 trianlges is checked for collision with a mesh with 1
  triangle, and 99 contacts are generated.
- The contacts are checked for correct value.
Merge branch 'master' into fix/TriangleTriangleContact
Merge branch 'master' into fix/TriangleTriangleContact
Merge branch 'master' into fix/TriangleTriangleContact
Fix after merge with master broke Collision UnitTests.

- The MeshShape::TriMesh is no longer available. Using the
  TriangleMeshBase instead.
Documentaion change to clarify the contact normal direction.
Bug fix in Triangle/Triangle contact calculation.

- The initial value of a line parameter has been set appropriately.
Merge branch 'master' into fix/TriangleTriangleContact
cpplint fix for one empty line: removed a tab.
Merge branch 'master' into fix/TriangleTriangleContact
Move physics based assertion from MeshShape to RigidRepParam::checkValidity

+ adjust the unit tests
+ adjust the doxygen doc
Fix Eigen aliasing issue in RigidRepresentationParametersTest
Merge branch 'fix/meshShapeVolumeAssertion' into 'master'

Move physics based assertion from MeshShape to RigidRepParam::checkValidity

+1: gsathyaseelan, Ryan Beasley, haizhouW

Merged-on: https://www.assembla.com/code/OpenSurgSim/git/merge_requests/753593
Merge branch 'master' into fix/TriangleTriangleContact
Add TriangleMesh(Plane/TriangleMeah)DcdContact to contact table in Physics.
Merge branch 'fix/TriangleTriangleContact' into 'master'

Bug fix in Triangle/Triangle contact calculation.

Merged-on: https://www.assembla.com/code/OpenSurgSim/git/merge_requests/738593