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
Looks like IE9 does not, which is a problem for travis. IE10/11 also use prefixed headers :( Just skip the test if ie is detected?