All these changes will allow us to more easily add Lol Engine as a
submodule of another Git project.

The containers no longer force the user to use the ptrdiff_t type for
size information. For convenience, size() now always returns an int,
and the size_s() method offers a way to handle arrays with more than
2 billion elements. Internally, we still use ptrdiff_t, though.

Since so much code had to be changed, I took the opportunity to get
rid of capitalised accessors for classes that are lowercase.

Reworked Primitive logic for scene rendering
FileUpdateTester works now .....

and 2) fuck the Visual Studio compiler that crashes when confused.

needs to know about Direct3D headers etc.

tested wherever relevant.

sub-millisecond but can be improved if we get rid of SDL timers.