casio/cfx9850.cpp: Various fixes

[qufb]

• Fix CFX9850GB display_ram mapping, this one doesn't write to segment 0x60;
• Debugger edits to register values were all being incorrectly applied to the first register, now they should go to the corresponding set of 4 registers;
• Implement TIME register;
• Add more instructions tested on hardware;
• Fix swap flags, they are always cleared regardless of values;
• Fix timer so that it expires on KO enabled key input;
• Add an infinite timer variant, which seems to only be used along with the low power variant of timer_wait;
• Prefer more accurate palette taken from an online Casio manual, although it isn't clear what contrast levels they used for those screenshots;

[cuavas]

Where does this one-second tick come from? Does the CPU have a secondary clock input? Is it an external 1-second tick input, or is it pre-scaled on the chip? (Seiko Epson PDA CPUs have a secondary oscillator that’s usually connected to a 32.768kHz watch crystal that has configurable dividers for generating the clock tick signal.)

[qufb]

There's a secondary 2-pin crystal oscillator that can be connected to the CPU, but it seems to be unrelated, since it's optional: it's present on Picky Talk, but on CFX9850GB both ends are connected with a resistor.

The 1-second tick feature is present on both systems. The way I measured it was by sampling the TIME register value after various timer waits, and it was being incremented roughly every second, including the cutoff at 60. It isn't very clear to me yet how the CPU is configuring this timer.