Assign a default value for categories_description

When generating a new category using EP4 while adding a new product, the category name is inserted; however, there has not been a description entered yet and therefore there was no data available to import.  A default ZC install does not assign a default value for the categories_description field within the categories_description table.  

This adds a default value; however, the database should be first queried to identify the existence of a default value.  If a default value is there, then either use the default value or don't include the categories_description when inserting that record.
This relates to #47.

admin/easypopulate_4_import.php

@@ -31,6 +31,8 @@
 
   $lid_first = $epdlanguage_id;
   $lid_first_code = $epdlanguage_code;
+
+  $cat_desc_default = ''; // Should evaluate the database to determine if one is already set and leave it alone if it is.
 
   $zco_notifier->notify('EP4_IMPORT_START');
 
@@ -939,7 +941,8 @@
                 $sql = "INSERT INTO " . TABLE_CATEGORIES_DESCRIPTION . " SET
                     categories_id   = :categories_id:,
                     language_id     = :language_id:,
-                    categories_name = :categories_name:";
+                    categories_name = :categories_name:
+                    categories_description = :categories_description:";
                 $sql = $db->bindVars($sql, ':categories_id:', $max_category_id, 'integer');
                 $sql = $db->bindVars($sql, ':language_id:', $cat_lang_id, 'integer');
 
@@ -983,6 +986,7 @@
                     unset($oldPost);
                   }
                   $sql = $db->bindVars($sql, ':categories_name:', ep_4_curly_quotes($thiscategoryname), $zc_support_ignore_null);
+                  $sql = $db->bindVars($sql, ':categories_description:', $cat_desc_default, $zc_support_ignore_null);
                 }
                 unset($v_categories_name_check);
                 unset($cat_lang_id);