Current issues

[arbrad]

1. The comparator for stable_sort is passed by value, not by reference, which is a performance issue as a HeuristicLitOrder object holds substantial data. [31 May 2015: Fixed by mgudemann.]
2. micAttempts is currently set to 3. It should be set to something much higher to allow more aggressive (but more expensive) inductive generalization.
3. One-SAT-context-per-frame is inefficient, as it turns out. There should be one context for all frames.
4. The logic cone should be loaded on-demand, not all at once.

Issues (1) and (2) are quick to fix, although I'm not currently maintaining the code.

Issues (3) and (4) are somewhat fundamental to the implementation.