Release candidate for v1.0.0

This release splits the original cyclejs npm package into two: @cycle/core and @cycle/web.

This is just a split, no functionality added nor removed nor changed. To migrate, you just need to get the right functions from the right packages.

They contain:

let Cycle = require('@cycle/core');
let {run, Rx} = Cycle;

let CycleWeb = require('@cycle/web');
let {makeDOMDriver, makeHTMLDriver, h, svg} = Cycle;