Allow comparison of framed vertices based on their vertex, not framed class...

I'd put this as an enhancement, but it might be controversial.  We're using frames mainly for adding/removing relationships rather than properties (which are handled in a generic manner), so all our frames interfaces extend VertexFrame to get access to the underlying node.

However I find I'm doing this an awful lot:

    if (frameTypeA.asVertex().equals(frameTypeB.asVertex())) {
       ... do something...
    }

I understand that a single vertex "framed" in two different ways might not be considered equal, but is there a case for adding a shortcut method to the VertexFrame interface to check this. Trouble is, I'm not sure what to name it - "sameAs", "isSameVertexAs". I'm happy to work up a pull request if this is considered a reasonable proposal.