Fix slave memory allocation
Merge branch 'master' into slave
Use 0.18 version of mesos
check for the driver being null before stopping it

a NPE was being thrown from here prior to this change.
Added support for setting the agent JVM args.
Fixed references to in-context help.
Merge pull request #34 from DealerDotCom/fix-help-context

Fixed references to in-context help.
Merge pull request #31 from DealerDotCom/mesos-version-update

Updated pom.xml to 0.18 version of mesos.
Merge pull request #32 from DealerDotCom/driver-null-check

Prevent possible NPE with closing Mesos driver.
Added the ability to customize JVM arguments.
Updated mesos dependency to 0.18.1.
Added Apache Maven repository to list of repositories.
Use slave memory setting to start the jenkins slave