Make default validators compatible with new gTLDs by no longer validating TLDs against a whitelist

Now that the gTLDs have hit the scene, the use case for validating a domain against a whitelist has become less practical.

Instead of the whitelist, this PR changes the default behaviour of the ```domain``` and ```email``` validators, to instead use the regexes that until now had been called ```domainRelaxed```, ```emailRelaxed``` etc.

This also supports the use case in #5 - even though that was already solved some months ago with commit 8db3cf90324