More livereload port flexibility in Gruntfile
ngIf foreignKeysHelp

Minor performance gain
Minor perf gain in value watch

Removes an ngClass and applies the needed class directly inside the
watch.
Merge pull request #470 from latin-language-toolkit/minor_perf

Very minor performance optimizations
Add ability to skip auth in specific modes

The configurator knows the general active mode and exposes a function
to check for it.
It's also the only place to instantiate Auth instances.

Auth instances can now be configured with an array of `skipModes` -
modes where the authentication routine is circumvented.

The configurator passes the mode function to the Auth instance, so that
it can check if authentication is required or not.

Closes #458