Fix condition/ConditionGroup.class.php when all conditions have no value.

Add page navigation mechanism.

git-svn-id: http://xe-core.googlecode.com/svn/branches/1.5.0-DB@8399 201d5d3c-b55e-5fd7-737f-ddc643e51545

classes/db/queryparts/condition/ConditionGroup.class.php

@@ -23,6 +23,8 @@
 					$cond_indx++;
 				}
 			}
+			// If the group has no conditions in it, return ''
+			if($cond_indx === 0) return '';
 			
 			if($this->pipe !== "")
 				$group .= ')';