Add makeViewMatrix utility function

adds a function to calculate a view matrix from eye, origin and up vector similar to gluLookAt()
Added documentation and renamed parameters
Class to encapsulate one pass in a multipass rendering algorithm
Add Light Depth Map to graphics examlp
Integrate Submitted version of RenderPass into local branch
Add Shadowmap shaders

Fix problem with near/far recalculation, at least temporarily ...
Shader updates, documentation, renaming
Enable Shaders to override underlying shaders from objects.

This lets shaders used in Renderpasses override actual material shaders that are assigned to objects
Update Graphics Example to render shadows on objects

Right now everything is 'hardwired' nothing can move without the rendering breaking
Test fixes

virtual function was not implemented in mock shader
replace mock shader with google mock
Fix Linux build warning
Fix bug in OsgShader where it had an unitialized variable

m_globalScope was not initialized as reported by valgrind on Linux
Fix issue when calling setGlobalScope on Shader
Merge branch 'feature/graphics-shadows-example' into feature/graphics-shadows-examples-2

Conflicts:
	Examples/GraphicsScene/ExampleGraphicsScene.cpp
	SurgSim/Graphics/Camera.h
	SurgSim/Graphics/OsgCamera.cpp
	SurgSim/Graphics/OsgCamera.h
	SurgSim/Graphics/RenderPass.h
Merge branch 'feature/accessible-properties' into feature/graphics-shadows-examples-2
Add behavior for simple behavior driven animation
Remove fixed 'Data' path from OsgSceneryObject

Also add a virtual interface in SceneryObject
Add Behavior to copy properties from one object to the other
Add Accessibility to Component and Representation
Utility method for creating a rigid transform so an object can point at something