Delete previous zip but not previous server directory by default
Don't use 'with' file context manager for backwards compatibility
Revert "Remove use of path module from omero directory"

This reverts commit e887016d899d490d556dbe21e4f83418fbb37fdc.
Return to using omero.cli.CLI for the new server

This partially reverts commit 626993f249faa21e4deda24cb677c3cf35997c5a