Add new feature and update default configs

[AlexVanMechelen]

This PR adds:

• An alternative feature to the cfg structure based features for all subgraphs. This new feature takes all nodes into account without subgraph extraction, and is thus faster to compute, but gives a slightly different result do to the absence of a duplicate node check.
• Updated default configs for CFG extraction. The default engine (vex) has a better overall performance than pcode, and the emulated method ensures the node at the entry point is extracted, providing more reliable results.