Add option to send mails without authentication
Fix formatting
Emailer calls AbstractMailer for useAuth property
Removed usesAuth variable from Emailer
Enable gzip compression on *DistTar tasks

Gradle now produces valid GZipped Tar archives.
Tested by running `./gradlew distTar` on Ubuntu 14.04.

Fixes #263
Merge pull request #311 from ReccaHokage/email-no-auth

Add option to send mails without authentication
Merge pull request #324 from wndhydrnt/fix_distTar_gzip

Enable gzip compression on *DistTar tasks
rebased from upstream to merge with useAuth flag changes