Support bytecode-based requests in interactive engine.

[siyuan0322]

Interactive engine already supports submit a script to query the remote graph, which syntax is like:
interactive.execute("g.V().count()").result().one().

However, there is also another bytecode-based style to query a graph, which should also be supported, as follows:
g.V().count().toList().

We should support bytecode-based style as it's the recommended style by Tinkerpop.