use nanomorph & bel 5

[yoshuawuyts]

This patch makes it so yo-yo and choo stay compatible, and it becomes trivial to switch one out for the other. We switched to nanomorph when morphdom introduced several regressions in a minor version bump, introduced a tooling requirement and started adding features that pushed it beyond just dom diffing. So far nanomorph has been quite alright, and I reckon it would make sense to keep the behavior the same (: Semver major for sure tho :v:

Changes

• replaces morphdom with nanomorph
• updates to bel@5

Notable changes

• Now weighs 1kb down from 4kb
• Event copying is now part of nanomorph, so no more custom logic in yo-yo
• The most notable one is that <input> elements must have a value=${myValue} attribute set when copying, rather than the value from the old node being persisted. This way the DOM truly becomes a function of the data, rather than having parts of it that need clearing logic.
• onload() no longer ships in bel@5
• nanomorph doesn't have a plugin system

[arturi]

Hi! Excited about this, is there any approximation as to when this could be merged?