Rename animation methods to avoid UKit conflicts

Fixes #2

demo/classes/ViewController.swift

@@ -8,17 +8,17 @@ class ViewController: UIViewController {
   override func viewDidLoad() {
     super.viewDidLoad()
     imageView.setAnimatableImage(named: "mugen.gif")
-    imageView.startAnimating()
+    imageView.startAnimatingGIF()
     UIApplication.sharedApplication().setStatusBarStyle(.LightContent, animated: false)
   }
 
   @IBAction func toggleAnimation(button: UIButton) {
-    if imageView.isAnimating {
+    if imageView.isAnimatingGIF {
-      imageView.stopAnimating()
+      imageView.stopAnimatingGIF()
       button.layer.backgroundColor = UIColor.whiteColor().CGColor
       button.setTitleColor(UIColor.blackColor(), forState: .Normal)
     } else {
-      imageView.startAnimating()
+      imageView.startAnimatingGIF()
       button.layer.backgroundColor = UIColor.clearColor().CGColor
       button.setTitleColor(UIColor.whiteColor(), forState: .Normal)
     }

source/UIImageView+Gifu.swift

@@ -10,8 +10,8 @@ extension UIImageView {
     }
   }
 
-  var isAnimating: Bool {
+  var isAnimatingGIF: Bool {
-    return animatableImage?.isAnimating() ?? false
+    return animatableImage?.isAnimating() ?? isAnimating()
   }
 
   var animatable: Bool {
@@ -39,15 +39,19 @@ extension UIImageView {
   }
 
   // MARK: - Animation
-  func startAnimating() {
+  func startAnimatingGIF() {
     if animatable {
       animatableImage!.resumeAnimation()
+    } else {
+      startAnimating()
     }
   }
 
-  func stopAnimating() {
+  func stopAnimatingGIF() {
     if animatable {
       animatableImage!.pauseAnimation()
+    } else {
+      stopAnimating()
     }
   }
 }