#4: Level editor supports enabling physics.
#4: Level loader loads physics attributes.
Check if animation is currently enabled, re-factor.
Added comment for new animation method.
Tons of bug fixes to add mingw support.
Even more mingw compilation bug fixes.

The final thing that needs to be fixed is a reference to
`std::this_thread` in Utilities/Timer.cpp. I'm not sure why it doesn't
exist.
Const-qualified collision.
Implementation is const-qualified too.
Implemented overload.
#4: Tested and improved level loading.
Added ability to shift order of scene entities.
Improved warnings to reflect new status.
#4: Fixed a a level loading bug.