Make specialization patterns for persistent premises more uniform.
Changes: - We no longer have a different syntax for specializing a term H : P -★ Q whose range P or domain Q is persistent. There is just one syntax, and the system automatically determines whether either P or Q is persistent. - While specializing a term, always modalities are automatically stripped. This gets rid of the specialization pattern !. - Make the syntax of specialization patterns more consistent. The syntax for generating a goal is [goal_spec] where goal_spec is one of the following: H1 .. Hn : generate a goal using hypotheses H1 .. Hn -H1 .. Hn : generate a goal using all hypotheses but H1 .. Hn # : generate a goal for the premise in which all hypotheses can be used. This is only allowed when specializing H : P -★ Q where either P or Q is persistent. % : generate a goal for a pure premise.