Start storing users

• New XML file, configurable from config file.
• =account register command
• Some way to delete your own account (=account delete) - with confirmation (=account deleteconfirm <mask>)
• Some way for admins to forcibly delete accounts (=account forcedelete <accountname>)
• Some way to change your email address (=account email <mail>)
• Don't force an email address to be stored
• Email confirmation before activation (=account verify <code>)
• Privacy policy for holding email address - T1234
• Timeout for email verification

XML

• root
  • users
    • user mask= mail= globalflags= mailconfirmed=
    • user mask= mail= globalflags= confirmationhash=
    • user mask= mail= globalflags=
    • user mask= globalflags=
    • user mask= globalflags=
    • ...