Wrong Reactionary dependence

exports/atom.coffee requires package `reactionary` while atom only has `reactionary-atom-fork` as a dependence (https://github.com/atom/atom/blob/master/package.json#L53). Should require `reactionary-atom-fork` instead.

It's clear that `Reactionary` will soon be omitted from atom's module exports, but as long as fallbacks are provided, the `reactionary` package reference should be corrected. :)
Updated deprecation msg to reactionary-atom-fork
:lipstick: create-a-package.md
Modernize advanced/configuration docs
Delete advanced/globals.md now that we cover them in the API docs
Suggest space-pen 4 rather than space-pen 3
Publicize checkpoint methods and deprecate open-ended transactions

On TextEditor

Signed-off-by: Max Brunsfeld <maxbrunsfeld@gmail.com>
:arrow_up: text-buffer to publicize checkpoint methods

Signed-off-by: Max Brunsfeld <maxbrunsfeld@gmail.com>
Prepare 0.152.0 release
:arrow_down: UI themes so we can iron out selector issues

Signed-off-by: Max Brunsfeld <maxbrunsfeld@gmail.com>
Add beginning of message system
Add a MessageManager to atom.messages
:memo:
Add some things to Message
Add specs for Message
nof
Export Message
Messages -> notifications
Use bug icon for fatal errors
Remove issue related stuff