fixed parsing of not in ATP proofs (e.g. ~x | y is (~x) | y, not ~(x | y))
fixed parsing of not in ATP proofs (e.g. ~x | y is (~x) | y, not ~(x | y))

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle