Convert export to plugin architecture, so that plugins are independant piece of code (RFE #1325937).

libraries/export/excel.php

@@ -0,0 +1,25 @@
+<?php
+/* $Id$ */
+// vim: expandtab sw=4 ts=4 sts=4:
+
+/**
+ * Set of functions used to build CSV dumps of tables
+ */
+
+if (isset($plugin_list)) {
+    $plugin_list['excel'] = array(
+        'text' => 'strStrucExcelCSV',
+        'extension' => 'xls',
+        'options' => array(
+            array('type' => 'text', 'name' => 'null', 'text' => 'strReplaceNULLBy'), 
+            array('type' => 'bool', 'name' => 'columns', 'text' => 'strPutColNames'), 
+            array('type' => 'select', 'name' => 'edition', 'values' => array('win' => 'Windows', 'mac' => 'Excel 2003 / Macintosh'), 'text' => 'strExcelEdition'),
+            array('type' => 'hidden', 'name' => 'data'), 
+            ),
+        'options_text' => 'strExcelOptions',
+        );
+} else {
+    /* Everything rest is coded in csv plugin */
+    require('./libraries/export/csv.php');
+}
+?>