* Mock up an “API response object” for the inbox notices
* Add in a fake “loading” delay
* Add placeholder mixin from Calypso
* Add a placeholder ActivityCard and styles
* Merge exports of placeholder into ActivityCard
* Add tests for placeholder card
* Update readme
* Switch placeholder content prop to a line count, rather than specific children
* Update tests for new lines prop
* Clear timeout when the inbox unmounts
* Add a test for 0 lines
Kelly Dwan