This allows us not to have to hack our definitions in the upstream files,
making it easier to upgrade to newer versions in the future.
For the include paths to work, the headers are moved to a GL subfolder to
match their upstream location.
-=-=-=-=-=-=-=-=-=-=
Build System:
-Big clean up of SCons, changed how builds are done to a much cleaner method (check the Github Wiki for instructions).
-Deactivated BlackBerry10 (sorry), if no mantainer found (or BlackBerry does not send us a Passort ;), platform will be removed as we have no longer devices to test.
Engine:
-Removed deprecated object and scene format (was in there just for compatibility, not in use since a long time).
-Added ability to open scenes even if a node type was removed (will try to guess the closest type).
-Removed deprecated node types.
