Merge pull request #5 from RonnyPfannschmidt/work

simplify caching by direct dict usage
direct table usage
Merge pull request #6 from RonnyPfannschmidt/work

Some more Work
removal of 1) lispish lists and 2) env parameters for variable alpha-equivalence
removal of copyleft notice from diff.css and nav.js because they will now be inserted into the HTML files
small changes
fix issue #7
other small changes
First experiment for Issue #8. Seems to work really well!
Merge branch 'master' of github.com:yinwang0/pydiff into work