removed a hack that leads to incorrect parsing of programs
improved $isConstArrayDeref
regenerated sum.cil.c to be sync with sum.c
simplified sum_spec.k
moved folder verification under tests
further simplified sum_spec.k
converted abstract syntax to concrete syntax in spec rule and got rid of the .Exps
Merge pull request #43 from yilongli/java_rewrite_engine

progress on (re-)proving the sum example