Add drawable scaled sprites

[acagliano]

As of right now, if you have a need to scale/draw a transparent sprite, you either have to sacrifice clipping or sacrifice scaling. Or write your own handlers for clipping and scaling, and wind up with less-optimal code than if it was just provided within the lib's routines.
For that reason, I'm proposing that:
gfx_ScaledRLETSprite(), and gfx_ScaledRLETSprite_NoClip() be added such that you can render scaled, clipped RLET sprites.

[mateoconlechuga]

RLET sprites will never support scaling and clipping. Use normal sprites for that.

I have changed the title to only be for gfx_ScaledSprite/gfx_ScaledTransparentSprite