Moved VirtualMailManager/Exceptions to VirtualMailManager/errors. Renamed VMM*Exception classes to *Error. No longer add the attribute 'message' to VMMError if it doesn't exist, like in Python 2.4. It has been deprecated as of Python 2.6. Also removed the methods code() and msg(), the values are now accessible via the attributes 'code' and 'msg'.

Config
   cfs - configset sect.opt val
   cfg - configget sect.opt

   ds - domainservices: smtp pop imap sieve???

- Aliases
    - avoid looping aliases

- Domain
    - optional limits for number of:
        + accounts
        + aliases
        + destinations/alias
        + alias domains