Merge pull request jessesquires#585 from dtsbourg/issue_492_scrollviewperformance

Rasterize collection view cell for scrolling performance, ref jessesquires#492

Author: jessesquires

JSQMessagesViewController/Controllers/JSQMessagesViewController.m

@@ -468,6 +468,9 @@ - (UICollectionViewCell *)collectionView:(JSQMessagesCollectionView *)collection
 
     cell.textView.dataDetectorTypes = UIDataDetectorTypeAll;
 
+    cell.layer.rasterizationScale = [UIScreen mainScreen].scale;
+    cell.layer.shouldRasterize = YES;
+    
     return cell;
 }