Patch 0.18.1

An update to the live version of the Online Go Server (OGS) was made this afternoon which enabled rengo matches. This patch updates The Conquest of Go to no longer display rengo matches and challenges coming from OGS, as The Conquest of Go does not have the features in place to fully support rengo matches at this time. Support for rengo within The Conquest of Go will be evaluated in the future as rengo becomes more mature and finalized on OGS.