Added support for an onError callback from Zeroclipboard.

Author: Will Fairclough

src/angular-zeroclipboard.js

@@ -34,6 +34,7 @@ angular.module('zeroclipboard', [])
         return {
           scope: {
             onCopied: '&zeroclipCopied',
+            onError: '&?zeroclipOnError',
             client: '=?uiZeroclip',
             value: '=zeroclipModel',
             text: '@zeroclipText'
@@ -64,6 +65,15 @@ angular.module('zeroclipboard', [])
               });
             });
 
+            client.on('error', function(e) {
+              if (scope.onError) {
+                scope.$apply(function() {
+                  scope.onError({$event: e});
+                });
+              }
+              ZeroClipboard.destroy();
+            });
+
             scope.$on('$destroy', function() {
               client.off('complete', _completeHnd);
             });