Call ipatch_close()

[derselbst]

Fluidsynth should call ipatch_close() to avoid memory leaks. This could be done by keeping track of created settings xor synth instances: When all instances of either type have been destoryed, call ipatch_close(). When the first instance is created again, call ipatch_init(). Need to figure whether settings or synth is more appropriate.

[derselbst]

... or make use of swami/libinstpatch#47 and always call ipatch_init() in new_fluid_synth() and ipatch_close() in delete_fluid_synth()

[jjceresa]

always call ipatch_init() in new_fluid_synth() and ipatch_close() in delete_fluid_synth()

This is the good solution and will work safely only if swami/libinstpatch#47 is applied. Otherwise Swami will fail (memory violation) during its deinitialization step because libinstpatch was already deinitialized by fluidsynth plugin when unloaded.