NEW mode for list thirdparty API (add supplier)

add new mode for more universel use of the api and easy switch between customer's and supplier's modes

htdocs/societe/class/api_thirdparties.class.php

@@ -117,6 +117,7 @@ public function get($id)
 	 * @param   int     $mode       Set to 1 to show only customers
 	 *                              Set to 2 to show only prospects
 	 *                              Set to 3 to show only those are not customer neither prospect
+	 *								Set to 4 to show only suppliers
 	 * @param   string  $sqlfilters Other criteria to filter answers separated by a comma. Syntax example "(t.nom:like:'TheCompany%') and (t.date_creation:<:'20160101')"
 	 * @return  array               Array of thirdparty objects
 	 */
@@ -143,6 +144,7 @@ public function index($sortfield = "t.rowid", $sortorder = 'ASC', $limit = 100,
 		if ($mode == 1) $sql.= " AND t.client IN (1, 3)";
 		if ($mode == 2) $sql.= " AND t.client IN (2, 3)";
 		if ($mode == 3) $sql.= " AND t.client IN (0)";
+		if ($mode == 4) $sql.= " AND t.fournisseur IN (1)";
 		$sql.= ' AND t.entity IN ('.getEntity('societe').')';
 		if ((!DolibarrApiAccess::$user->rights->societe->client->voir && !$socids) || $search_sale > 0) $sql.= " AND t.rowid = sc.fk_soc";
 		//if ($email != NULL) $sql.= " AND s.email = \"".$email."\"";