MIDI Update

[a740g]

This PR moves MIDI support in QB64-PE out of $UNSTABLE. Additionally, it addresses the issue highlighted here.

Changes:

• The compiled executable will no longer include an embedded soundfont.
• To address the issue discussed in the forum, ymfmidi, Opal, and a tiny FM bank are now used.
• Soundfonts can be loaded using the _MIDISOUNDBANK command.
• Depending on the sound bank type, a suitable MIDI rendering backend is selected.
• The available backends are primesynth (SF2), TinySoundFont (SF3, SFO), and Opal (AD, OPL, OP2, TMB, WOPL).
• For Windows users, a VSTi 2.x based renderer that is configurable by the user is also provided.
• Multiple MIDI file formats are supported: MUS, HMI, HMP, HMQ, KAR, LDS, MDS, MIDS, RCP, R36, G18, G36, RMI, MID, MIDI, XFM, XMI
• The use of $UNSTABLE:MIDI and $MIDISOUNDFONT triggers an appropriate warning message.

New command:

_MIDISOUNDBANK fileName$[, flags$] ' flags$ can be "memory" and one of the supported soundfont/FM bank types