Rewrite patch algo / improve diffing performance #499

I want to rewrite patch to incorporate some prefix/suffix trimming techniques as described in the first link posted below.

Hyperapp unkeyed and keyed fares relatively well according to js-framework-benchmarks (arguably the best benchmark out there and by far), but we could do a bit better and still get away with our 1 KB proposition.

• Appending rows to a large table. #216 (comment)
• https://github.com/yelouafi/petit-dom/blob/master/src/vdom.js