Add option to send mails without authentication
Fix formatting
Email should retry on SocketTimeoutException  - issue #322
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
Updated code based on code review feedback
Merge pull request #311 from ReccaHokage/email-no-auth

Add option to send mails without authentication
change the default max attachment size to more readable
Simplify max attachment size checking logic
changes due to method name change in EmailMessage class
Merge pull request #324 from wndhydrnt/fix_distTar_gzip

Enable gzip compression on *DistTar tasks
rebased from upstream to merge with useAuth flag changes
removed trailing spaces
Merge pull request #326 from Victsm/validator-plugin

Validator plugin
Merge pull request #323 from hluu/master

Email should retry on SocketTimeoutException  - issue #322
For job with retry - the attempt count doesn't match with log file when inserting into database. Issue #331
minor update from codereview feedback
Merge pull request #332 from hluu/master

For job with retry - the attempt count doesn't match with log file when inserting into database - issue #331
Change the default concurrent execution option to skip execution issue #333