This will remove any template content related to the trade currency if
that one is left empty in the configuration.
While going through the templates I also cleaned up the PHP Warnings
left. The code and templates should now process without throwing any PHP
warnings.
Fixes#305 and further addresses #301
* Currently no GUI, use DB access to change the row entry
* Upgraded Database table `accounts` with upgrade SQL
* Updated `admin` field to `is_admin` as boolean
* Modified pages, classes, templates to support is_admin and is_locked
Addresses #147