ii leader mode (#76)

* initial impl of ansible -> TXo leader OK

* leader mode with programmable addrs etc, works w/ TXo

* leader mode octave + track select

* fix some issues with leader track selection

* fix leader mode cfg not working on all grid apps

* fix i2c follower octave calculation + flash saving

* use TO.TR instead of TO.TR.P for er301 triggers

* split follower controls out to separate functions

* mode selection for different followers works

* fix velocity scaling, some parameter UI

* leader mode rework ok

* fix some issues with cv/gate mode and octave offsets

* release polyphonically allocated notes

* fix preset key, JF.MODE, and voice alloc bugs

* reorder JF.MODE 0 and JF.TR 0 for maybe fewer pops?

* send TXo trigger messages in lower byte

* also use 4-byte message for TO.ENV

* restore / change all TXo settings when switching state

* don't retune values sent to followers

* silence followers when resuming apps

* add doc defs for leader mode settings

src/ansible_arc.c

@@ -79,7 +79,7 @@ void set_mode_arc(void) {
 		clock = &clock_null;
 		// clock = &clock_levels;
 		// clock_set(f.levels_state.clock_period);
-		init_i2c_slave(II_LV_ADDR);
+		if (!leader_mode) init_i2c_slave(II_LV_ADDR);
 		process_ii = &ii_levels;
 		resume_levels();
 		update_leds(1);
@@ -94,7 +94,7 @@ void set_mode_arc(void) {
 		clock = &clock_cycles;
 		// 24
 		clock_set(DAC_RATE_CV << 3);
-		init_i2c_slave(II_CY_ADDR);
+		if (!leader_mode) init_i2c_slave(II_CY_ADDR);
 		process_ii = &ii_cycles;
 		resume_cycles();
 		update_leds(2);