v1.0.0-beta.4

This is a minor beta that only brings the following:

• Add PHENOMIC_APP_BASEURL env variable (entire baseUrl option as a string)
  (in
  3799fa8
  by @MoOx)
• @phenomic/plugin-rss-feed: fail with a http 500 if rss feed fail to be
  generated (in
  26c8d95
  by @MoOx)
• @phenomic/plugin-bundler-webpack: Make root for App.js configurable (in
  78ecd47
  by @airtonix)
• @phenomic/plugin-renderer-react: fix issues with class attributes (coming
  from markdown) (in
  927aea2
  by @MoOx)
• Internal refactoring by @MoOx

Website has been a WIP for a few month now, mostly due to a break @MoOx took
from his keyboard.

Stable 1.0.0 is missing a change for the database engine that is currently
causing performance issues during development as soon as you get a hundred of
pages. All efforts are currently on this improvement.

For Reason users

• Upgrade bs-platform to 4.x and reason-react to 0.5.x (in
  6067bc9,
  1e4de9a
  and
  086c0af
  by @MoOx)