connector: document Connector and ConnectorConfig interfaces
connector: document Connector and ConnectorConfig interfaces

closes #203

Tecsisa/dex,sercand/dex,Tecsisa/dex,sercand/dex,andrewstuart/dex,zlabjp/dex,Tecsisa/dex,jhuntoo/dex,andrewstuart/dex,zlabjp/dex,sercand/dex,jhuntoo/dex,andrewstuart/dex,zlabjp/dex,jhuntoo/dex