Display application status in tip for needs attention number

Summary:
Also splits blocking and active revisions.

This could display 0 with non-empty tip over it.
It's intentional meaning that 0 objects need your attention but there is still some work to do.

Test Plan: Hovered over number.

Reviewers: epriestley, chad

Reviewed By: chad

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5049