Export UGDK_HEADERS for any project using UGDK as subdirectory
Remove all references to the script system.

Conflicts:
	CMakeLists.txt
	cmake/CreateBindings.cmake
	cmake/languages/Lua.cmake
	cmake/languages/Python.cmake
	modules/ugdk-core/src/system/engine.cc
	src/module/ugdk_desktop_2D.i
	src/module/ugdk_graphic_2D.i
	src/module/ugdk_input.i
	src/module/ugdk_resource_2D.i
	src/module/ugdk_system.i
	src/module/ugdk_ui_2D.i
	src/swig_module_list.cmake

Conflicts:
	CMakeLists.txt
Don't try to run ugdk_script_test in travis.