work on existential quantifiers
fixing bug with verification of answer tuples in answer patterns with anonymous variables
fixing deadlocks due to free/malloc being called from signal handler

(this is not allowed, as it might lead to a heap deadlock
 if interrupting another malloc/free calll)

(now the reaction time to signals is a bit lower but no I was
 not able to reproduce any more deadlocks)
logging PID when killed
add an example for ExistsPlugin
forgot to initialize terminationRequest
add hash external atom
introduce two benchmark counters
small fix in Greedy heuristics
small improvement in Greedy heuristic
Merge remote-tracking branch 'origin/master' into release2x
bugfix in decision level update
two questions/warnings
additional (deactivateable) benchmarking for initialization of ClaspSolver
experiments with satelite