Adding the checkpointing boolean flag as a new cloud config parameter and setting the default values for fields in config.jelly which can be overridden by users. Also bumping up the org.apache.mesos version number in pom.xml from 0.13.0 to the latest stable 0.16.0 release.
Merge pull request #19 from ahunnargikar/slave-checkpointing

Added checkpointing option to the Jenkins scheduler.