feat(scope): new and improved scope implementation

- Speed improvements (about 4x on flush phase)
- Memory improvements (uses no function closures)
- Break $eval into $apply, $dispatch, $flush
- Introduced $watch and $observe

Breaks angular.equals() use === instead of ==
Breaks angular.scope() does not take parent as first argument
Breaks scope.$watch() takes scope as first argument
Breaks scope.$set(), scope.$get are removed
Breaks scope.$config is removed
Breaks $route.onChange callback has not "this" bounded

test/service/cookieStoreSpec.js

@@ -16,7 +16,7 @@ describe('$cookieStore', function() {
 
   it('should serialize objects to json', function() {
     $cookieStore.put('objectCookie', {id: 123, name: 'blah'});
-    scope.$eval(); //force eval in test
+    scope.$flush();
     expect($browser.cookies()).toEqual({'objectCookie': '{"id":123,"name":"blah"}'});
   });
 
@@ -30,12 +30,12 @@ describe('$cookieStore', function() {
 
   it('should delete objects from the store when remove is called', function() {
     $cookieStore.put('gonner', { "I'll":"Be Back"});
-    scope.$eval(); //force eval in test
+    scope.$flush(); //force eval in test
     $browser.poll();
     expect($browser.cookies()).toEqual({'gonner': '{"I\'ll":"Be Back"}'});
 
     $cookieStore.remove('gonner');
-    scope.$eval();
+    scope.$flush();
     expect($browser.cookies()).toEqual({});
   });
 });