Added skeleton for downloading any URIs in the CommandInfo
Added todos for automatically decompressing some archives
Mount the sandbox into the container
Pass through mesos environment variables and re-write MESOS_DIRECTORY
Set the working directory of the container
Add MESOS_RECOVERY_TIMEOUT and check to ensure the environment var exists
Added some comments
Comment about supporting HADOOP_HOME
Fix for sandbox paths with colons in them :-(
Support for HTTP URIs