Workflow inputs and outputs now support 'to' and 'from' properties
respectively, replacing 'flow' property on each.
Nodes now support declarations of multiple properties on each outflow, a
'to' property on outflows, and a 'from' property on inflow expressions.
Nodes now support declarations of multiple properties on each outflow.
Updated tests to reflect new support for declarations of multiple
properties on each node outflow.
Updated test resources to reflect new support for declarations of
multiple properties on each node outflow, and new 'to' and 'from'
properties on workflows, inflows, and outflows.