brew compatible openni2 interface

	modified:   cvt/io/OpenNI2Camera.cpp
	modified:   cvt/io/OpenNI2Camera.h
fixed variable name to capitals

	modified:   ../cvt/CMakeLists.txt
added fallback value if out of bounds to interface

	modified:   cvt/vision/rgbdvo/KeyframeData.h
refactoring of dvo interfaces

	modified:   cvt/CMakeLists.txt
	modified:   cvt/vision/RobustWeighting.h
	new file:   cvt/vision/rgbdvo/CostFunction.h
	new file:   cvt/vision/rgbdvo/DVOCostFunction.h
	modified:   cvt/vision/rgbdvo/GNOptimizer.h
	modified:   cvt/vision/rgbdvo/IntensityKeyframe.h
	modified:   cvt/vision/rgbdvo/KeyframeData.h
	modified:   cvt/vision/rgbdvo/LMOptimizer.h
	deleted:    cvt/vision/rgbdvo/Linearizer.h
	modified:   cvt/vision/rgbdvo/Optimizer.h
	new file:   cvt/vision/rgbdvo/PhotometricError.h
	modified:   cvt/vision/rgbdvo/RGBDKeyframe.h
	new file:   cvt/vision/rgbdvo/RGBDPreprocessor.h
	modified:   cvt/vision/rgbdvo/RGBDVisualOdometry.h
	modified:   cvt/vision/rgbdvo/RGBDWarp.h
	new file:   cvt/vision/rgbdvo/ReferenceFactory.h
	modified:   cvt/vision/rgbdvo/SystemBuilder.h
recognizing clang compiler

	modified:   cmake/CompilerFlags.cmake
adding exitDelegates to application

 - when application exits, signal all registered
   callback, e.g. in order to clean-up/stop threads, ...

	modified:   cvt/gui/Application.cpp
	modified:   cvt/gui/Application.h
fixing group recognition in ConfigFile

	modified:   cvt/util/ConfigFile.cpp
removing semicolons and fixing indent

	modified:   cvt/gui/internal/OSX/ApplicationOSX.h
requiring calib.xml inside RGBD Dataset folders!

	modified:   cvt/io/RGBDParser.cpp
changing include guard

 - temporary -> this class should be removed later on

	modified:   cvt/math/CostFunction.h
indent fix

	modified:   cvt/util/ParamSet.h