participants-database.php
initial options array merge required typecast

PDb_Settings class
changed default setting to 'email' for both field ID settings
eliminate get_email_column method, we just need to use the string for the default value

git-svn-id: https://plugins.svn.wordpress.org/participants-database/trunk@822076 b8457f37-d9ea-0310-8a92-e5e31aec5664