Preliminary work for upmixing & general cleanup. Fixes basic issues in games such as Shovel Knight and slightly improves the LEGO games. Upmixing stitll needs to be implemented.
Audio levels in a few games will be fixed as we now use the downmix coefficients when possible instead of supplying our own
While were at it, we can also enable sign conversion warnings and other
common warnings as errors to prevent these from creeping back into the
codebase.
