Fixing windows compilation issues.

CMake/FindAssimp.cmake

CMake/SuperBuild/External_SFML.cmake

CMake/SuperBuild/SuperBuild.cmake

CMakeLists.txt

Collision/UnitTests/CMakeLists.txt

ContactHandling/CMakeLists.txt

ContactHandling/UnitTests/CMakeLists.txt

Devices/CMakeLists.txt

Event/CMakeLists.txt

Event/UnitTests/CMakeLists.txt

Examples/CMakeLists.txt

Examples/vegaFem/CMakeLists.txt

Examples/vegaFem/main.cpp

IO/CMakeLists.txt

Rendering/CMakeLists.txt