Added variant of eres_inst_tac that operates on indexnames instead of strings.
Added variant of eres_inst_tac that operates on indexnames instead of strings.

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