added topleveldomain guesser

added a topleveldomain guesser to map tlds to a locale.
f.e:
domain.ch will map to locale de_CH

this is usefull for sites with more than one tld to provide a default locale per tld.

mappings can be influenced via config.
how does this work exactly? does this guesser also work with totally different domain names, like "reisen.de", "travel.com" and "voyager.fr" or something like that?