implement lanes. see sul-dlss/workflow-multiplexing#43
uses new lane_id workflow service API
add stub for get_lane_ids
use dor-workflow-service 1.7.0
Add defined? check for WORKFLOW_TIMEOUT constant
Merge pull request #20 from sul-dlss/feature-robot-allocation

implement lanes

Added defined? check for WORKFLOW_TIMEOUT in config/boot.rb