[TIMOB-2695] iOS crop property to image views.

(from [8924a7783bf5dc7e7d5c3e478ce437b8f23eb199]) [#2695 state:in-progress] Implemented as a blob's imageAsCropped method. Takes one argument with width, height, x, and y properties. Test needs to be created before sending to fixed. https://github.com/appcelerator/titanium_mobile/commit/8924a7783bf5dc7e7d5c3e478ce437b8f23eb199"> https://github.com/appcelerator/titanium_mobile/commit/8924a7783bf5...

Tested on 1.6 with the following code and it works as expected:

   var cropImage = function(imageView,width,height,x,y){
       // with the var 'a' we avoid the image to triger the 'load' listener infinite times
       var a = 1;
       imageView.addEventListener('load',function(){
           if(a==1){
               imageView.image = imageView.toBlob().imageAsCropped({width:width,height:height,x:x,y:y});
           }
           a++;
       });
   };
   // example:
   var win = Ti.UI.createWindow();
   win.backgroundColor=backgroundColor='#ccc';
   var imageWidth=180;
   var imageHeight=100;
   var imageX=200;
   var imageY=10;
   var photo = Ti.UI.createImageView({
       image:'http://www.google.com/images/logos/ps_logo2.png',
       top:50,
       left:120,
       width:imageWidth,
       height:imageHeight
   });
   cropImage(photo,imageWidth,imageHeight,imageX,imageY);
   win.add(photo);
   win.open();
   

Resolving ticket as per the above.