: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
Export Notification, not Message
Notification::getTimestamp()
Remove unnecessary error flash classes
Prepare 0.153.0 release
Merge pull request #4264 from atom/bo-messages

Messages API implementation
:arrow_up: autocomplete@0.33.1
Fix ordering of panels in panel containers

An off-by-one error caused new panels to be inserted later
in the document than intended.
Merge pull request #4309 from atom/mb-fix-panel-order

Fix ordering of panels in panel containers