Start single frame when plunger released

as opposed to when it is first pressed. It is with great consternation
that I make this change. The original intention of the Trigger()
feature was to be instant, but having used the intervalometer on
several rolls now, I find the extra frame that this feature introduces
into sequences to be troublesome.

ino/intval2_buttons.ino

@@ -171,8 +171,6 @@ void button_start (int index) {
     if (sequence) {
       sequence = false;
       Output(2, 250);
-    } else  {
-      Trigger();
     }
   }
 }
@@ -185,6 +183,8 @@ void button_end (int index, long buttontime) {
         Output(2, 250);
       }
       Trigger();
+    } else {
+      Trigger();
     }
   } else if (index == 1) { //set direction
     if (buttontime < 1000) {