Merge pull request #22 from drzax/settings-patch

Allow editing of site title in settings screen.
Make translations for Site records accessible in CMS.
Make translated homepages (children of translated Site records) accessible on the frontend.
If the requested URLSegment isn't found in the default site, attempt to find it in translations.
BUGFIX Incorrect site sometimes cached in the Multisites singleton.
BUGFIX Return the correct part of the $map.
BUGFIX Make sure array key exists before attempting to access it.
Give templates access to the homepage for a given site

This is necessary when using the Translatable module otherwise it's not
possible to get the link for a translated homepage of a site.