iOS fixes: debugging and logging

This does a few things to make iOS a viable platform for development:

 * Stops CMake from setting Release/Debug/RelWithDebInfo/MinSizeRel all to have no debugging symbols and no optimization. (why, cmake, why, why would that be your default?)
 * Forces cityhash and zlib always to build at fast, since debugging them probably is not interesting.
 * Adds an option to install unit tests at build time (kinda slow) and uses a different path on iOS.  This seems like the easiest way...
 * Deletes the PPSSPP binary every build to force Xcode to relink it.  Xcode won't do that automatically no matter how much static libraries change (at least with iOS), apparently.
 * Enables console logging when `_DEBUG` even on mobile.
 * Fixes a path being incorrect (outside Documents/ directory) on iOS.  This may affect people's save files but earlier is better imho to fix something like this.

Potentially some of the above may affect Mac as well (or any Xcode target, specifically the optimization level ones are likely too, only figured that out by reading CMake's source code)... but I have fought with CMake enough for today.

-[Unknown]