Handle much more characters from the Unicode codeset in expressions. While there: FIX: Add forgotten Punctuation characters `?' and `@'. While there: Allow the escaping of single and double quotes that normally start a string (e.g. for expressions like f' is the first derivation of f).

include .hg* *.txt *.ini
graft LICENSES
graft docs
graft tests
prune docs/_build
global-exclude *.pyc *.pyo