chore(ngCsp): add e2e tests

Also changes `connect:devserver` and `connect:testserver` to conditionally serve files with csp headers when the path contains `.csp` somewhere.

Depends on https://github.com/angular/dgeni-packages/pull/70 to be merged and updated dgeni-packages to be included in angular.js
Not sure how I feel about this; if I understand correctly, this clears **all** errors, but returns only the severe ones?