Follows most of the changes made to the gint driver system.
* Replace test gint/switch with a new test gint/drivers which shows
driver metadata, flags, and world states.
* Enable the DMA Control test on SH4-based fx-9860G.
* Enable the Memory Speed test on SH4-based fx-9860G.
* Enable the Memory Speed test on SH3-based fx-9860G although there's
barely anything useful for that platform.
* Update all tests to the GINT_CALL API when useful.
* Use public world buffers and public driver state structures to show
world states without having to coordinate the gint and gintctl code.
* Added the switch menu
* Added the keyboard menu on fx-CG 50
* Added a (currently unused) bold 8x9 font on fx-CG 50
* Displayed something decent in the "Image Rendering" test on fx-CG 50
* Changed F-keys all around to unify the semantics
* Improved the layout of the RAM detection test
* Adapted TMU/ETMU display to the new mpu/timer.h definitions
* Added a timer selector in the F-key bar in the timer test
* Added an "external libraries" tab that will also test libc features
* Added a libimg test