manage_fields.js
selecting a captcha form element presets validation and other settings

manage_fields.php
captcha fields are now readonly

participants-database.php
form validation now occurs for editors in the admin, administrators will only have signup forms validated
updated new prefixed class names: xnau_Image_Handler

pdb-retrieve-default.php
prefixed classname updated

PDb_FormElement class:
both image and filename are now shown in the admin edit form
prefixed class names updated

PDb_List_Admin class:
added "stuffbox" class to list table for bottom margin

Several classes renamed, files renamed

git-svn-id: https://plugins.svn.wordpress.org/participants-database/trunk@811117 b8457f37-d9ea-0310-8a92-e5e31aec5664