fix(sliderView): find width properly when element is transformed

Fixes #1313

Author: ajoslin

js/views/sliderView.js

@@ -60,7 +60,7 @@ ionic.views.Slider = ionic.views.View.inherit({
       slidePos = new Array(slides.length);
 
       // determine width of each slide
-      width = container.getBoundingClientRect().width || container.offsetWidth;
+      width = container.offsetWidth || container.getBoundClientRect().width;
 
       element.style.width = (slides.length * width) + 'px';