Menu with icons, aggregated relation status

Menu items with styles applied on per-endpoint basis.

lint.

Responding to review - doc-blocks around new functions
Merge pull request #118 from makyo/relation-menu-2

Relation menu now shows icons based on aggregated relation status.  Additionally, endpoints as listed in the menu are styled per each endpoint's status (endpoints in error are shown in red).  Action remains delete, for now, but all other actions remain available through inspector.

QA with `/:flags:/relationCollections`, deploy Mysql and Wordpress, bump Wordpress to 100 units, and wait for a relation error.  Check that the menu displays proper icons and colors endpoints based on error/running status.