BREAKING CHANGE All imports from 'angular2/core/compiler' should be changed to 'angular2/compiler'.
Closes #5079
This is moving ngUpgrade into the main repository per #4838. The ngUpgrade is published from the main import consistent with https://docs.google.com/document/d/1rbVTKTYLz6p2smQNYI8h4-QN-m2PS6F3iQIDmSzn0Ww/edit#heading=h.6cxvr9awtf5r Closes #4931