Fixes/tuning in boxes
Fixes/tuning in boxes

- added flag to disable boolean reasoning
- tuned condition that makes convex boxes
- use of Cudd_CountPath instead of Ldd_PathSize
- factorized to_intervals
- disabled code that attempts at refining the result of widening. This
  causes non-termination with some non-simplified ssh programs.

seahorn/crab,seahorn/crab