Menu with icons, aggregated relation status

Menu items with styles applied on per-endpoint basis.

lint.

Responding to review - doc-blocks around new functions
Fire destroy-inspector event when a zip is dropped on the canvas fixes #1278559
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.
Merge pull request #121 from hatched/inspector-covered-1278559

__To QA__
Deploy a charm and open the service inspector.
Drop a .zip onto the canvas and the old inspector should close and the series-select inspector should open.
Fixed bug #1278663 tab text overflowing in Safari.
Fixed bug #1276861 tab scroll height not adjusting in Safari.
Fixed bug #1276844 tabview animating into place on page load in Safari.