Add tests for escaped template calls.
Make escaped punctuation templates illegal in 1.6.

There's a minor bug with escaped templates in 1.6 and I don't have time to
fix it, this will help limit its effect. As far as I'm aware no one uses
escaped templates with punctuation templates. Escaped templates are an
undocumented feature anyway.
Be a little smarter about skipping escaped templates.

Only possible since I made escaping punctuation templates illegal.
Some notes about recent quickbook changes.
Split up the language version chapter.
Stop mismatched brackets causing an error with old quickbook.

Mismatched brackets are only an error for quickbook 1.6+.