feat(simulator): tick on out of bounds elementChanged

This ensures we can use the existing `elementChanged` logic
if the simulation is not currently running, i.e. when
configuring the simulator pre-execute.

lib/simulator/Simulator.js

@@ -255,6 +255,12 @@ export default function Simulator(injector, eventBus) {
 
   function elementChanged(element) {
     changedElements.add(element);
+
+    // tick, unless jobs are queued
+    // (and tick is going to happen naturally)
+    if (!jobs.length) {
+      emit('tick');
+    }
   }
 
   function scopeChanged(scope) {

test/spec/simulator/SimulatorSpec.js

@@ -32,6 +32,20 @@ describe('simulator', function() {
       expect(spy).to.have.been.calledOnce;
     });
 
+
+    verify('sub-process', (simulator) => {
+
+      // when
+      const spy = sinon.spy();
+
+      simulator.on('tick', spy);
+
+      simulator.waitAtElement(element('SUB'));
+
+      // then
+      expect(spy).to.have.been.calledOnce;
+    });
+
   });
 
 
@@ -142,6 +156,7 @@ describe('simulator', function() {
 
     });
 
+
     describe('scopeChanged', function() {
 
       it('should emit on scope creation');