Remove hidden fields from queries, fixes #4334

Squashed commit of the following:

commit 138a25d80166a28a7768846fc14198d1ffcbbb0f
Author: José Raddaoui Marín <raddaouimarin@gmail.com>
Date:   Sat Dec 28 22:57:13 2013 +0100

    Remove hidden fields from all fields queries

    Check hidden fields for unauthenticated users in the current template
    and remove those from the all fields queries in advanced search
    and the search box

commit b2f7fd79caa22cc953adc267b3775a2faf171589
Author: José Raddaoui Marín <raddaouimarin@gmail.com>
Date:   Sat Dec 28 22:47:46 2013 +0100

    Make loadMappings function public and static