[META] Make cyclejs scope hoistable

[jvanbruegge]

This is basicly a meta TODO list for stuff that is causing a ModuleConcatenation bailout with webpack.
Concatenating modules removes unneccesary webpack wrapper functions and improves loading and execution time.
Still todo:

• xstream extra operators in own package (or main package), importable via es modules
• ES Module build for xstream
• ES Module build for cycle-onionify
• ES Module build for cycle-storageify (Add ES6 module build maiermic/cycle-storageify#10)
• ES Module build for @cycle/storage
• Remove Polyfills from DOM (Fix sibling isolation implementation in DOM driver #759)
• Use ES module imports for snabbdom
• Split @cycle/time packages to remove mockTimeSource from bundle (chore(META): split @cycle/time into multiple packages #673)
• Rewrite snabbdom-selector (pulls in a lot of unneeded dependencies)
• Remove @cycle/run/lib/adapt (gets included multiple times) (Cycle with plugins (low-level drivers + adapters) #760)

[staltz]

I'm tagging this "bug" because it's like something that should be behaving differently, and we don't currently use the label "enhancement" anywhere.

[jvanbruegge]

Rewrite snabbdom-selector is done with #805

[jvanbruegge]

Remove polyfills is now done