chore($sniffer): make msie variable public

The msie variable is a global variable used within the ng core which contains the
version number for the current Internet Explorer browser that is rendering the
application. Other modules outside of the ng core could make use of this variable
instead of having to rollout duplicate detection code. This code makes it easy to
reuse this simple property within the $sniffer service.

src/ng/sniffer.js

@@ -83,7 +83,8 @@ function $SnifferProvider() {
       csp: csp(),
       vendorPrefix: vendorPrefix,
       transitions : transitions,
-      animations : animations
+      animations : animations,
+      msie : msie
     };
   }];
 }

test/ng/snifferSpec.js

@@ -333,4 +333,8 @@ describe('$sniffer', function() {
       });
     });
   });
+
+  it('should return true for msie when internet explorer is being used', inject(function($sniffer) {
+    expect($sniffer.msie > 0).toBe(window.navigator.appName == 'Microsoft Internet Explorer');
+  }));
 });