Summary: Fixes T5090. Introduced getIcon into Handle stack which allows you to specify a per handle icon. getIcon falls back ot getTypeIcon.
Test Plan: changed the icon on a project a bunch. verified transactions showed up. verified icon showed up in typeahead. verified icon showed up in tokens that were pre-generated (not typed in). units test passed.
Reviewers: chad, epriestley
Reviewed By: epriestley
Subscribers: epriestley, Korvin
Maniphest Tasks: T5090
Differential Revision: https://secure.phabricator.com/D9264
