Sync UF Match should limit to individuals

When syncing between a CMS user account and a civi contact record, the search should be limited to civi 'Individual' contacts. An organization should never have a login, and should be maintained via an admin through a relationship. This also helps minimize the possibility that a CMS user syncs to the wrong contact type if they happen to have shared address information (for example, a business-oriented site where most user's addresses are also a work address) and the following confusion and difficulty in correcting the mis-match.

We've been using this minor change in production since the 2 tree with no problems.