Fix arbitrary path limits and improved error handling (exit
even if not built with asserts).
sort and remove some includes
Refactored part of KleeHandler construction so that
- A fixed size buffer is no longer used for output Directory path
  (would of failed for large paths).
- KLEE warns about the presence of klee-out-* files that aren't
  directories.
- We don't get stuck in an infinite loop if there aren't available
  directories.