status: Column output format with timestamps displayed

This iteration of the status command prints the output in a column display.  It now prints the timestamp of the deployment in the form YYYY-MM-DD HH:MM:SS, as well as a truncated checksum, and the osname and refspec.  The command also now has a --pretty option which prints the output in a row format for readability and user friendliness.  This command will be important for a system administrator who needs to see details of the deployments and know which version of the OS they are booted into.