registerMember

Registers a member to the forum. Allows two types of interface: 'guest' and 'admin'. The first includes hammering protection, the latter can perform the registration silently. The strings used in the options array are assumed to be escaped. Allows to perform several checks on the input, e.g. reserved names. The function will adjust member statistics. If an error is detected will fatal error on all errors unless return_errors is true.