Makes `CelSprite` unowned and adds a new `OwnedCelSprite` class for
owned sprites.
This clarifies ownership and makes the code cleaner in a number of
places.
Additionally, because the `CelSprite` class is now tiny (1 less
pointer), we can pass it by-value instead of by-reference, removing a
pointer indirection in the rendering functions.
Clips `CelBlitOutlineTo` to the output buffer.
The templated implementation means that this compiles to many
case-specific functions with near-branchless inner loops.
Increases binary size by 92 KiB.
This should gradually replace all the direct rendering of game texts
throughout the code. The interface is made to closly mirror that of the
art fonts as that is what will eventually be used for rendering Unicode
fonts both in the menus and ingame.
fixup! ✨ Generic game text render function