The format is almost identical to CL2, except it uses the frame header
to store frame width and height instead of 5 32-line offsets.
This means we always have access to frame dimensions, so we can use it
as an on-disk format for our graphics as well.
Additionally, we may be able to optimize the rendering even more
in the future now that we have guaranteed knowledge of frame dimensions.
* Add MakeRectangle helper to convert from SDL_Rect
* Add Rectangle::inset method for shrinking a rectangle
Turns out some of the other use cases I though this could apply to were actually doing something based on a fixed region
* Simplify initialisation of settings menu rects
- Use UiOkDialog() to display all error messages
- Add SDL simple message, and console fallbacks to UiOkDialog()
- Boot graphics early on to facilitate most error messages with build in
gui
- Some more miniwin clean ups