Merge pull request #1 from whitequark/master

Add ocamlbuild rules; improve token definition lexer.
show location on error in automerr
allow token names with lowercase letters in them
Merge branch 'master' of https://github.com/whitequark/merr
make lexers a little more consistent
Merge pull request #1 from pippijn/master

show locations in automerr and allow lowercase letters in token names