prove_case_equation now calls uses meta_eq_to_obj_eq to cope
with new form of 'split'. Tried calling simp_tac instead of using resolution
with trans, but it was significantly slower: 98.3 secs instead of 91.2 secs
for ex/Enum.
#! /bin/sh
#rm-logfiles: remove useless files from subdirectories
rm log */make*.log */make*.log.gz
rm */test
find . -name '.*.thy.ML' -print -exec rm {} \;