feat(pager): change controllerAs to pager

BREAKING CHANGE: As part of the split of the pager component from the
pagination component, this changes the controllerAs use to `pager` from
`pagination`

Closes #4961

Author: wesleycho

src/pager/pager.js

@@ -17,7 +17,7 @@ angular.module('ui.bootstrap.pager', ['ui.bootstrap.pagination'])
     },
     require: ['uibPager', '?ngModel'],
     controller: 'UibPaginationController',
-    controllerAs: 'pagination',
+    controllerAs: 'pager',
     templateUrl: function(element, attrs) {
       return attrs.templateUrl || 'uib/template/pager/pager.html';
     },

src/pager/test/pager.spec.js

@@ -54,7 +54,7 @@ describe('pager directive', function() {
   });
 
   it('exposes the controller on the template', function() {
-    $templateCache.put('uib/template/pager/pager.html', '<div>{{pagination.text}}</div>');
+    $templateCache.put('uib/template/pager/pager.html', '<div>{{pager.text}}</div>');
 
     element = $compile('<uib-pager></uib-pager>')($rootScope);
     $rootScope.$digest();