Style fixes

- selector conditionals
- alignment of parameters
- indentation consistency
- Unix line endings
Re-factoring to support LMTP setup through dovecot::lmtp

- needed correct package installed
- didn't belong in master since imap already isn't
- sets up 20-lmtp.conf via augeas for protocols and postmaster address
- fails if dovecot::base::protocols does not contain 'lmtp', as it is a requirement of using the lmtp protocol, otherwise it is ignored
Merge pull request #14 from andschwa/lmtp

LMTP class re-factoring
add possiblity to override task specific configuration file