dyncom: Implement UMAAL

armemu: Fix SSAT16.

armemu: Should be using labs for USAD8/USADA8

armemu: Implement USAD8 and USADA8

armemu: Implement SMLSD

armemu: Implement QASX and QSAX

Pica progress: Texturing, shaders, cleanups & more

More specifically, this also fixes crashes by Citra trying to load a src2 register even if the current instruction does not use that.

Makes for cleaner and faster code.

This allows for proper emulation of the different CMP/LRP/MAD instructions.

Pica/CommandProcessor: Fix vertex decoding if multiple memory areas are accessed for different attributes.

This effectively adds support for a lot texture formats in the rasterizer.

This was caused by the framebuffer display widget not checking whether we are actually in a valid emulation state or not.