Resolved duplicate package declaration error

Also simplified os lookup for packages.

Comment for mailplugins regarding undef

Fixed messed-up pathing for files and destinations.

Template wasn't generating correctly.

changed <% @whatever -%> to <%= @whatever %>.
Merge pull request #23 from tthayer/master

Fixed RHEL issues with init.pp and made auth-passwd template work.
update spec helper
adapted travis ci build
fixed sieve setup
Add parameters ssl_cipher_list and ssl_prefer_server_ciphers
Add header information for better syntax highlighting
Add possibility to overwrite configuration files from package
dovecot::postgres: Add possibility to specify database port
WIP: dovecot::logging: Enable log_timestamp configuration
dovecot::postgres: Make dovecot-sql.conf.ext template configurable
dovecot::postgres: Make dovecot-sql.conf.ext template configurable
dovecot::mail: Only add user, if not defined somewhere else
Remove duplicate test for 'dovecot-pgsql'
Remove trailing space