Error when creating and fetching conference members

[TobiasLounsbury]

I encountered two errors with the conference class.
getMembers() relies on the existence of ConferenceMembersCollection extending CollectionObject. This was not implemented and thus caused a missing class error to be thrown.

Conference->addMember does properly create the member, but when attempting to fetch the newly created member information from the API, it fails to pass in the memberId and so causes a resource not found error to be thrown.

I've traced and patched both of these and will initiate a pull request.