Add an event to allow extension developers the ability to filter the template variables used to create the memberrow array (used for displaying the list of users).

$memberrow is created at line 1800 in memberlist.php; there is no way to filter the template variables set up during the initialisation of the variable meaning that you cannot add data into the memberrow template variable.

A new event should be added that includes at least the following:

• user_id
• row
• memberrow

That would add sufficient data into an event for extension developers to extend the memberlist without having to write expensive code to achieve simple results.