SubgraphStrategy in OLAP

If a vertex filter is provided in SubgraphStrategy, then it will turn any edge step in the traversal into something like:

...outE().filter(inV().vertexFilterCondittion())

This breaks any OLAP traversal (leaving the star graph) and is not even the behavior that you would always want. We should have an option to disable the adjacent vertex checks. In code this would just mean to replace this else: https://github.com/apache/tinkerpop/blob/master/gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/strategy/decoration/SubgraphStrategy.java#L92
...with else if (checkAdjacentVertices).