Tags: ARMSX2/ARMSX3

Release 0.3.1

Add PPU and SPU cache clearing

Two rows under a Compiled Code Cache section on the Performance tab, next to the
recompiler settings and separate from the shader cache on the Renderer tab, which
holds GPU pipelines rather than recompiled code.

The layout is <files>/cache/cache/, with ppu-<hash>-<name> directories for
firmware modules at the top level and <TITLEID>/ppu-<hash>-EBOOT.BIN per game.
The SPU cache is a spu-*.dat inside those, so the two options are not symmetric
and are worded accordingly: clearing SPU removes only those files and leaves
booting as fast as it was, while clearing PPU removes the directories outright
and necessarily takes the SPU caches with them.

Both report how much was freed, and both refuse while a game is loaded, since a
running VM holds those files open and is still writing to them.

Fold build instructions into the README

BUILDING.md was RPCS3's desktop build guide and had nothing about Android, so it
was misleading here. Removed it and put real Android build steps in the README
instead. Also dropped the status file, it was working notes and not much use to
anyone reading the repo.