pre_process_cf_header
function to display the customfields in a nextmatch table-header with the functionality of sorting and selecting
by customfields. Of cource you need to adapt the source of your get_rows or search functionality to do the
actual sorting and selecting. We try to do some additional documentation in codecorner
You can pass the allowed/wanted fields to the header by passing an array of the wanted fields to the widget
through the options parameter (see the eTemplate editor for fields/cells). This array is passed on through
$cell['size']. By now the array passed through is only working, if it is the only entry in the optionsparameter.
The allowed fields array assumes an numerical indexed array of (an) array(s) with ['name'] tag(s) set.
The name provided assumes a preceding #. (e.g.: $allowed_fields[x]['name']='#MyCustomField')
Admin can now define multiple addressbooks each with an own edit / view template and an own icon.
Atm. all Addressbooks are stored in one backend, but this will change soon^tm
