Remove edge cloning alias methods, use Graph instead

[clue]

// old (removed alias methods)
$new = $edge->createEdgeClone();
$inverted = $edge->createEdgeCloneInverted();

// new (already supported before)
$new = $graph->createEdgeClone($edge);
$inverted = $graph->createEdgeCloneInverted($edge);

// old (rarely used)
$walkGraph = $walk->createGraph();

// new (already supported before)
$walkGraph = $graph
    ->createGraphCloneEdges($walk->getEdges())
    ->createGraphCloneVertices($walk->getVertices());

Builds on top of #175