Summary
- tuned whitespace
- compile
- added 'corec' examples and tests
- file header
- added two 'corec' examples
- document addition of 'corec'
- moved 'corec' from ssh://hg@bitbucket.org/jasmin_blanchette/nonprim-corec to Isabelle
- put all 'bnf_*.ML' files together, irrespective of bootstrapping/dependency constraints