Add quest objectives to the minimap

Summary:
Add important objectives (like waygates and quest markers) to the minimap.

This also probably fixes @cspeckmim's bug with the @ keyboard shortcut.

Test Plan:
(This is probably easier to undestand if you arc patch + click around.)

Reviewers: chad, amckinley

Reviewed By: chad

Subscribers: cspeckmim

Differential Revision: https://secure.phabricator.com/D17955