Optimize the Combinatorial machine implementation

[TonyTroeff]

Think of a way to isolate dependencies as early as possible.

[TonyTroeff]

Thoughts:

1. Give priority to initialization categories (utilities) that define more demands.
2. Keep track of the "blocked" utilities. If at any point all utilities for a given category are blocked, stop further processing.

[TonyTroeff]

The first bullet was implemented in PR #42. It all started as a PoC to see if this approach will optimize the generation of combinations or not. This PoC was successful - there were even benchmark observations to prove it.

The second bullet is still not implemented.