ENH: Make physx optional

See merge request iMSTK/iMSTK!618

BUG: remove superflous consistency check

See merge request iMSTK/iMSTK!621

BUG: use a direct check for light existence

See merge request iMSTK/iMSTK!619

Add tests to the scene

See merge request iMSTK/iMSTK!615

Remove name from the light class. It is now maintained exclusively in the scene class.

Removes isLightRegistered, hasSceneObject
Adds removeLight

REFAC: change way requirements are set in filters

See merge request iMSTK/iMSTK!617

additionally adds a way to add optional requirements

Add code coverage target, fix linux warnings

See merge request iMSTK/iMSTK!612

REFAC: Adds bilinear interpolation toggle to Textures

See merge request iMSTK/iMSTK!614

ENH: Adds SSAO

See merge request iMSTK/iMSTK!599

- move the implementation to the cpp
- enforce const correctness
- add more descriptive documentation for certain functions

Refactor to add computBoundingBox to the entire scene
Remove Renderer::updateConfig and do the update in the setConfig itself
Remove unused include in the imstkKeyboardSceneControl

ENH: Created custom inflatable constraints and custom inflatable PBD object

See merge request iMSTK/iMSTK!613

ENH: Created custom inflatable constraints(volume and distance) whose rest volume and length can be modified. Created custom inflatable pbd object and example demostrating injection procedure.

REFAC: PbdConstraintFunctors and Containers

See merge request iMSTK/iMSTK!610

Did not touch imstkPbdModel as it's being worked on by andrew wilson

BUG: Fix PhysX linking in linux debug

See merge request iMSTK/iMSTK!611

Known issue, has to be built explicitely, needs lcov installed

ENH: Add tests for neighbor vertices and triangles

See merge request iMSTK/iMSTK!607