Support for custom Table Name, and Moved the Username field to the main table (BC-BREAK)

its now possible to choose the names of the users and user_custom_fields table, using the fields :+1: 'userTableName' and  'userCustomFieldsTableName' in user options. As for now they are defaulted to their current names.

The username field is now in the main table. the calls have been updated to reflect this. As for the BC BREAK, if the user want to migrate, the sql and mysql scripts contains an update that will add the missing field. 
all is left now is to add an update script that will insert the username value in the table. couldn't find to proper sql syntax tonight. Might try tomorrow ...