Merge branch 'cmake_external_updates' into 'master'

CMake/External/CMakeLists.txt

CMake/External/External_Assimp.cmake

CMake/External/External_Eigen3.cmake

CMake/External/External_GoogleTest.cmake

CMake/External/External_LibNiFalcon.cmake

CMake/External/External_PThreads.cmake

CMake/External/External_PhysX.cmake

CMake/External/External_SCCD.cmake

CMake/External/External_SFML.cmake

CMake/External/External_Uncrustify.cmake

CMake/External/External_VRPN.cmake

CMake/External/External_VTK.cmake

CMake/External/External_VegaFEM.cmake

CMake/External/External_g3log.cmake

CMake/External/External_glfw.cmake

CMake/External/External_gli.cmake

CMake/External/External_glm.cmake

CMake/External/External_imgui.cmake

CMake/External/External_tbb.cmake

CMake/External/Patches/physx.cmake