Merge pull request #8 from wyrie/master

Additional parameters
Merge pull request #9 from wyrie/master

Fix for changes in adfac9202020aa612a64e037034344b88ce6f8ae
improve lmtp support
improve sieve support
support NFS storage
allow custom auth-passwdfile configuration
Merge pull request #11 from fraenki/mod

additional parameters for LMTP, SIEVE, AUTH and NFS
Added parameters for client workarounds, login process control and shared storage.