Spike, all major stuff is there, just ugly and untested as fuck

In particular : filtering trees mostly works, which really opens up nice
possibilities.
Expand the README
Rename Triplet => Node, NodeList => List
Make all Hexp::Node normalized
Make the tests green again
Expanded the README
Take out the filtering again for now, make the Nokogiri domizing testable.
First pass at getting the metrics to pass

This is necessary so this can go to master without breaking the
build. I still need to address or whitelist the reek smells before merging.
Test coverage is high, but flay, flog and yardstick need some love.
Test / flog / flay / reek / refactor cycle completed