Fix incorrect handling of boundary conditions in PlyReader
Default constructor for TriangleMesh
Add update function to collision representation
Add Deformable collision representation and render test
Fem3D Ply reader, add global material

- The last material added is used for all fem elements.
Fem3DRepresentation, add loadfile

- Remove loadFem from staple example
- Adds methods to set/get filename, manually loadFile, and automatically
load file during initialization.
- Modify Fem3d ply reader to update an attached fem3d, rather than
produce its own fem3d.
- Update unit test and adds unit test.
Cpplint fixes
Fem3d representation loadFile, prevent validity assertion
Add KeyboardBehavior interface for stapling demo example.
Use template to register graphics representations in KeyboardBehavior.

Also add time filter to suppress possible multiple calls to update
the keyboard for each single key pressed.
Control the frequency to detect if a key has been pressed.
Clean up revised code.
Use integer as key in unordered_map m_keyRegister
Enable FEM of the wound
Restructured setCollisionRepresentation

other review and documentation fixes
Rename KeyboardBehavior to KeyBoardTogglesGraphicsBehavior.
Update include headers for KeyboardTogglesGraphicsBehavior class.
Move KeyboardTogglesGraphicsBehavior class into SurgSim::Blocks.
Remove static keyword for local variable and revise code and fix style.
Fem3dRepresentationTests, add extra loadFile tests