added reset parameter to stop function Animation controller (#730)

Added a reset parameter to the CoreAnimationController stop function, by
default it's true so there are no regressions.

The reason for this change is that currently if you use the stop
function the values will reset to their start values which is not handy
if you want to chain the same value to a different animation.

Author: jfboeve

src/core/animations/CoreAnimationController.ts

@@ -63,14 +63,16 @@ export class CoreAnimationController
     return this;
   }
 
-  stop(): IAnimationController {
+  stop(reset = true): IAnimationController {
     this.unregisterAnimation();
     if (this.stoppedResolve !== null) {
       this.stoppedResolve();
       this.stoppedResolve = null;
       this.emit('stopped', this);
     }
-    this.animation.reset();
+    if (reset === true) {
+      this.animation.reset();
+    }
     this.state = 'stopped';
     return this;
   }