Remove couple of circular dependency between modules in Angular 2 ES5 output caused by exception_handler.ts and router_providers.ts.
Fix the build/checkCircularDependency gulp task to call madge properly to detect the circular deps.
Closes#7287
This is part of ongoing work to make core platform-independent.
BREAKING CHANGE
All private exports from 'angular2/src/core/facade/{lang,collection,exception_handler}' should be replaced with 'angular2/src/facade/{lang,collection,exception_handler}'.