added event.timestamp and event.delta to collision events, closes #368

Author: liabru

src/core/Engine.js

@@ -149,8 +149,13 @@ var Body = require('../body/Body');
             Sleeping.afterCollisions(pairs.list);
 
         // trigger collision events
-        if (pairs.collisionStart.length > 0)
-            Events.trigger(engine, 'collisionStart', { pairs: pairs.collisionStart });
+        if (pairs.collisionStart.length > 0) {
+            Events.trigger(engine, 'collisionStart', { 
+                pairs: pairs.collisionStart,
+                timestamp: timing.timestamp,
+                delta: delta
+            });
+        }
 
         // iteratively resolve position between collisions
         var positionDamping = Common.clamp(20 / engine.positionIterations, 0, 1);
@@ -178,11 +183,21 @@ var Body = require('../body/Body');
         Engine._bodiesUpdateVelocities(allBodies);
 
         // trigger collision events
-        if (pairs.collisionActive.length > 0)
-            Events.trigger(engine, 'collisionActive', { pairs: pairs.collisionActive });
+        if (pairs.collisionActive.length > 0) {
+            Events.trigger(engine, 'collisionActive', { 
+                pairs: pairs.collisionActive, 
+                timestamp: timing.timestamp,
+                delta: delta
+            });
+        }
 
-        if (pairs.collisionEnd.length > 0)
-            Events.trigger(engine, 'collisionEnd', { pairs: pairs.collisionEnd });
+        if (pairs.collisionEnd.length > 0) {
+            Events.trigger(engine, 'collisionEnd', {
+                pairs: pairs.collisionEnd,
+                timestamp: timing.timestamp,
+                delta: delta
+            });
+        }
 
         // clear force buffers
         Engine._bodiesClearForces(allBodies);