Small custom preset upgrades, plus misc commits

[InsaneFirebat]

• The "load last preset" shortcut is now compatible with custom presets
• Pressing left/right on a custom preset slot page will change to the prev/next page
• Fixed reversed first round mid patterns in Phantoon RNG controls
• Fixed inoperable save station after loading a preset into a save room
• Optimizations for ih_game_loop_code and compensation in artificial lag
• Added Dyce menu palette profile Edit:
• Cycle through palettes to toggle gameplay backgrounds in the crash handler