Add a new instance field denoting run status

This patch modifies Rapi, the Cluster.loadData and hscan serialization to load
and save the instance run status. At instance level, we add both a boolean
field denoting the true/false run status, and a string field which holds the
original value (since we don't have a 1-to-1 mapping) for use in hscan
serialization.

The run status is not yet used.