Initial pass at enabling lazy loading for AngularJS.
  - This is an expansion of
https://groups.google.com/forum/#!topic/angular/w0ZEBz02l8s
  - This change set has been tested in production, need to add unit
tests to the standard build.
  - Load modules with angular.require, automatically compile and digest
  - Load modules with $injector.require
 
Updated plugins.js to invoke gulp directly.