mod_base/core: added 'qarg' argument to postback actions.
Enables adding the value of input elements as query args to the postback.
mod_base: removed default error strings from validations. They are more often wrong than useful.
mod_base: moved the e-mail validation regexp to z_stdlib's z_email_utils.erl.
mod_authentication: fixes for password reset e-mail and some error feedback messages.
mod_admin_identity: added a control to add/verify e-mail identities instead of the e-mail address input for a person.
The verification is done by sending an e-mail with a verification link that needs to be followed.
Added extra maintenance functions to m_identity.
Added observer for #rsc_update_done{} to copy new e-mail addresses to the identity model.