#7: emphasized the CAN vs CANNOT vs MUST by writing them upper case in the disclaimer
#7: first working implementation of entailments
no unit tests yet
#7: added lexicon entries to allow parsing "eat" without objects in all tenses,
w.g. "he eats", "we will_eat"
#7: extracted propTense from entailments so it can be used in isSatisfiedProp as well
(as mentioned in discussion to #6)