First pass at a simple drag and drop API, allowing you to accept files dropped into your application.

This way subclasses can use it without a lot of casting.

Thanks to Vittorio Giovara for the patch!

Thanks to Vittorio Giovara for the patch!

Thanks to Vittorio Giovara for the patch!

This isn't strictly needed by SDL, but it's a good example for other projects.

Fixed where we set the content scale - it's used by the renderbufferStorage:GL_RENDERBUFFER_OES call.

Thanks to Marcus von Appen for the patch!

In landscape mode the frame stays the same, and the transform property is modified with the appropriate rotation.
The touch coordinates are rotated by the transform, so if I want to normalize them by the frame rect, I have to transform the frame rect first.

To answer the FIXME, no, we shouldn't force this.  The fullscreen flag implies borderless behavior even though the flag isn't set on the window (in case fullscreen is toggled)

The iOS driver sets the fullscreen and shown flags on the window during creation, so we need the mode code to be aware of that, since none of the other fullscreen/shown code paths get run.
FIXME: Maybe we need a better way of detecting that?

Fixed list loop caused when there are two entries in the list and the one being returned is already at the head.

Fixed SDL applications being killed immediately after being backgrounded, because they were trying to draw while minimized.

Thanks to Martin Gerhardy for the patch!

--HG--
rename : src/libm/math.h => src/libm/math_libm.h

The draw color affects RenderClear() as well.  (thanks to the feedback form to whoever pointed this out)

Update SDL_HasClipboardText functions to return value based on clipboard content; Fix memory leak in fallback SetClipboard implementation

Thanks to Mason Wheeler for the fix!

Thanks to Patrick Baggett for the fix!