Fix http port 80 issue.
Upgrade to Mesos 0.18.2

* Mesos 0.18.2
* Chaos 0.5.6
* Scala 2.10.4
Remove email message for jobs that will be retried
Unify notification prefix on "[Chronos]"
Merge pull request #221 from mesosphere/mesos-0.18

Upgrade to Mesos 0.18.2
[chronos-sync] Permit .yaml or .yml suffix.
Merge pull request #225 from airbnb/notification-changes

Notification changes
Add mvn dependency:tree as before_script entry to aid debugging.
Set explicit script element
Disable travis' default mvn install
Remove before_script
fixed logging link in readme
Added validation for chronos-sync.
[chronos-sync] Improve logging.
Prefer offers with reserved resources, first.
Update the job correctly when disabled.
Fixed bad exception handling.
Switch to new `launchTasks` signature.
Merge pull request #237 from airbnb/backports

 Backports
C* driver bump.