setuichange: throw if custom drag on some modes

If custom drag handler is added together with mode updown or leftright
throw an exception.

apps/setuichange/ChangeLog

@@ -1,3 +1,5 @@
 0.01: New App!
 0.02: Fix case where we tried to push to Bangle.btnWatches but it wasn't
 	defined.
+0.03: Throw exception if trying to add custom drag handler on mode updown and
+	leftright.

apps/setuichange/boot.js

@@ -39,6 +39,7 @@ Bangle.setUI = (function(mode, cb) {
     try{Bangle.buzz(30);}catch(e){}
   }
   if (mode=="updown") {
+    if (options.drag) throw new Error("Custom drag handler not supported in mode updown!")
     var dy = 0;
     Bangle.dragHandler = e=>{
       dy += e.dy;
@@ -55,6 +56,7 @@ Bangle.setUI = (function(mode, cb) {
       setWatch(function() { b();cb(); }, BTN1, {repeat:1, edge:"rising"}),
     ];
   } else if (mode=="leftright") {
+    if (options.drag) throw new Error("Custom drag handler not supported in mode leftright!")
     var dx = 0;
     Bangle.dragHandler = e=>{
       dx += e.dx;

apps/setuichange/metadata.json

@@ -1,6 +1,6 @@
 { "id": "setuichange",
   "name": "SetUI Proposals preview",
-  "version":"0.02",
+  "version":"0.03",
   "description": "Try out potential future changes to `Bangle.setUI`. Makes hardware button interaction snappier. Makes it possible to set custom event handlers on any type/mode, not just `\"custom\"`. Please provide feedback - see `Read more...` below.",
   "icon": "app.png",
   "tags": "",