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.
Merge pull request #12 from wyrie/master

Added parameters for client workarounds, login process control and share...