Merge pull request #2 from sergeypavlenko/master

Port module to D7
Query Extender implemented
Use db_select with extend('FormFilterAPI') instead of db_query
$_SESSION[$session_name] could be empty
support < > >= =operations

example:
$filters['action']= array(
              '#type'  => 'select',
              '#title' => t('Payments'),
              '#where' => array('operation' => "pgt.amount"),
              '#options' => array(
                '> 0' => t('received'),
                '< 0' => t('sent'),
              ),
            );
Merge branch 'master' of https://github.com/itpatrol/formfilterapi

Conflicts:
	formfilterapi.info
	formfilterapi.module
	formfilterapi_example/formfilterapi_example.module