Roadmap to 1.0

Crude roadmap to 1.0. May change!
The most important is to agree on the API before it Drab reaches 1.0.

Features:
* [ ] commander/handler test framework
* [x] unify API (bang functions)
* [x] work with CI
* [x] unify shared and standard commander
* [x] integration tests for broadcasting functions
* [x] remove all limitations of Drab.Live
* [x] move Live.Cache to module instead of DETS
* [x] should not steal existing client-side events (`addEventListener()`)
* [x] support for multiple Drabs in umbrella

Hard depreciations:
* [x] Drab.Client.js()
* [x] Drab.run_handler()
* [x] events handler declaration long form (drab-event & drab-handler)
* [x] Drab.Browser.console!/2
* [x] Drab.Browser.redirect_to!/2
* [x] Drab.Core.broadcast_js!/2
* [x] handlers running without `public` declaration will raise
* [x] poke and peek API change