Emulation improvements
- CPU: Fix fir_mov logic for MULS instruction
- PPU: Improve blending over transparent pixels
- PPU: Draw blended sprites in depth layer order
- SPU: Support wave-in software mix channel
- SPG200: Add watchdog emulation
UI changes
- Add SPU output visualization window
- Add memory editor
- Add support for selecting and loading ROMs from UI
- Add setting for allowing background gamepad input
- Fix border artifacts in bilinear fullscreen mode
- Ignore keyboard presses for controller input if ImGui window has focus
- Add icon, FreeDesktop desktop entry file
- Add About window
- Disable imgui.ini