fixes #37 render chips on commas

dist/angular-chips.js

@@ -417,7 +417,7 @@
     /*@ngInject*/
     function ChipControlLinkFun(scope, iElement, iAttrs, chipsCtrl) {
         iElement.on('keypress', function(event) {
-            if (event.keyCode === 13) {
+            if (event.keyCode === 13 || event.keyCode === 44) {
                 if (event.target.value !== '' && chipsCtrl.addChip(event.target.value)) {
                   event.target.value = "";
                 }

src/js/directives/controls/chip_control.js

@@ -16,7 +16,7 @@
     /*@ngInject*/
     function ChipControlLinkFun(scope, iElement, iAttrs, chipsCtrl) {
         iElement.on('keypress', function(event) {
-            if (event.keyCode === 13) {
+            if (event.keyCode === 13 || event.keyCode === 44) {
                 if (event.target.value !== '' && chipsCtrl.addChip(event.target.value)) {
                   event.target.value = "";
                 }

test/basic_flow_spec.js

@@ -42,6 +42,15 @@ describe('Directive chips : Basic flow', function() {
         expect(scope.samples[scope.samples.length-1]).toBe('Spain');
     });
 
+    it('pressing Comma key (,) on INPUT element should add the chip',function(){
+        var inputEle = element.find('INPUT')[0];
+        inputEle.value = 'Italy';
+        var event = new Event('keypress');
+        event.keyCode = 44;
+        inputEle.dispatchEvent(event);
+        expect(scope.samples[scope.samples.length-1]).toBe('Italy');
+    });
+
     it('check deleting chip by passing string', function() {
         isolateScope.chips.deleteChip(scope.samples.indexOf('Pramati'));
         expect(scope.samples.indexOf('Pramati')).toBe(-1);