Pack disconnected graph components using new utility

[ugurdogrusoz]

Let's pack the disconnected graph components using the new utility as suggested in its README. We should add a new option to this layout though named packComponents, which is true by default to control the use of this facility.
Let's make sure layout is applied to each component separately to speed up layout, followed by packing.
Notice however that fcose that uses the same code base as this one also packs components. We wouldn't want to do redundant packing here.