added signature of method separateModifierTag()
case 1 of method separateModifierTag()
separateModifierTag() finished, not tested yet
fixed a bug in tagSentenceWithMT() for handling null
1) wrap text and pattern in methods isMatchedNullSafe() and isEntireMatchedNullSafe() 2) fixed a bug in wrapupMarkup()
1) fixed a bug in wrapupMarkup(). 2) Tested separateModifierTag() on Buckup_1998 data set.