Push called GraphicsObject::execute() up to GraphicsSystem

This is general code, shouldn't be in SDLGraphicsSystem.
Object mutators should be held by the Object, not by the GraphicsSystem.

My first design was incorrect. I assumed that I'd have to add object execution
since I didn't see it in GraphicsSystem. It was actually in
SDLGraphicsSystem. This moves ownership of mutators to the GraphicsObject.

96bdeb8e03d39f8798afea03fe21b1916d6c5a45 tried to address this same problem,
but didn't address the root cause: objClear and friends should halt running
mutators.
Fix order of arguments.
Support a second scaling factor

RealLive appears to support a second scaling factor on objects.
Smooth animations by uploading objects outside of timing loops.

In rec/grp heavy games, the correct thing is *not* to upload loaded images to
the GPU, because they'll be blitted to one of the DCs. But when using objects,
we want to make sure that the data is on the graphics card by the time the load
command completes because otherwise there will be a noticeable lag in any
animation that uses the object.
Speculative fix for the rotating "VS" in the Little Busters battle system.

This changes details about how images are blown up (the change to
glTexParameteri), and how images are scaled and rotated. This makes the
rotating VS look closer to RealLive.exe (but its not perfect).
Use both child and parent object properties while rendering.

LB and Tomoyo After set properties on parent objects to translate or fade all
children of the parent. Add/average these values together, as appropriate.

(This makes the computer text align correctly in Tomoyo After, and makes the
characters move in LB's battle system.)
Implement button object selection.

LB uses a new select() command which doesn't work like any other. It
instead relies on GraphicsObjects that have been placed on screen with
some additional metadata. LB uses this to ask whether you want to disable
various minigames, I think?
Make sure effects and text objects are uploaded to smooth animations.