Optimize the fetching of a saas a little by not even trying to see if there is multiple saas for the same hostname.

A model side validation should validate this beforehand instead, or simply ignore if there is multiple sass's objects for the same host and use the first one.
Merge branch 'master' of github.com:rafaelgaspar/saasable

Conflicts:
	lib/saasable/mongoid/saas_document.rb
Version bump to 4.0.1
Regenerate gemspec for version 4.0.1