added worker_disconnect_timeout when all workers disconnect from slicer
added worker_disconnect_timeout when all workers disconnect from slicer

terascope/teraslice,godber/teraslice,godber/teraslice,jsnoble/teraslice,jsnoble/teraslice,terascope/teraslice,terascope/teraslice,godber/teraslice,terascope/teraslice,jsnoble/teraslice,jsnoble/teraslice,jsnoble/teraslice