This reverts commit ac536d2f.

Unfortunately we must rely on these in Purr Data. It's impossible to
enumerate every single function signature, especially given some are
dynamically loaded at runtime.

Fonts may not yet line up properly, especially in room_sim_3d where fontsize
is used to show z position. Also, no effort was made to improve the interface
of these classes. For example, size changes don't bump the source values
back within the bounds of the object.

ALSA MIDI backend: Quick and dirty fix for bogus zero-velocity note-off messages; output a note-on with zero velocity instead.