Plugfest 2018: Electronic Key Segment is not respected by Message Router object (Explicit Messaging)

An electronic key segment in the request path of an explicit message toward the message router object is tolerated, but not evaluated/verified, nor rejected properly if an invalid electronic key is specified.

The error codes specified in the specification Vol.1 "Table 5A-3.33 Electronic Key Segment Error Response Values" should apply for mismatching electronic keys.

On the implementation level, handling of electronic keys should be consolidated between the message router and the connection manager object's for the sake of maintainability and reduced size of the codebase.