splits process_action up to handle records separately (#329)

* implements leader key for planck experimental

* allows override of leader timeout

* adds ability to use the leader key in seq

* fixes leader keycode

* adds chording prototype

* fixes keycode detection

* moves music mode to quantum.c

* disables chording by default

* adds music sequencer functionality

* implements audio/music functions in quantum.c

* splits up process_action to allow independent processing of actions

* merging?

quantum/keymap_common.h

@@ -191,6 +191,9 @@ extern const uint16_t fn_actions[];
 
 #define RESET 0x5000
 #define DEBUG 0x5001
+#define KC_LEAD 0x5014
+
+
 
 // MAGIC keycodes
 #define MAGIC_SWAP_CONTROL_CAPSLOCK      0x5002