got LEDs working, ribbon trail program initially implemented

- fixed soft I2C master set hi/lo routines
- fixed bug in matrix_send not setting all LEDs from map
- fix AWU interrupt not firing; requires EXTI line to be configured too even if unused
- fixed wrong dividers used in system clock set function

firmware/app/led/matrix.h

@@ -13,7 +13,7 @@
 // 0 index = bottom.
 // 0 value = no LED here.
 typedef struct LedMap {
-    uint8_t ribbon[80];     // a "linear" bottom to top map, with gaps for the spacing.
+    uint8_t ribbon[88];     // a "linear" bottom to top map, with gaps for the spacing.
     uint8_t a[20];          // left to right, bottom to apex to bottom.
     uint8_t ii_lf[5];       // top to bottom.
     uint8_t ii_rt[5];       // top to bottom.
@@ -22,6 +22,7 @@ typedef struct LedMap {
 
 
 extern LedMap led_set;
+extern uint8_t awled_fade[6*12];