Ember-tether bumped to 0.4.1

• #162 - Bumps ember-tether dependency to 0.4.1. This brings about additional functionality and improvements:
  • Fixes event delegation issues in test suites where events and actions were fired but not caught by Ember
  • Upgrades the Ember CLI dev environment
  • Exposes findTooltip and findTooltipTarget as public helpers (code here). Public documentation will follow.
  • Makes tooltips render as a child of the Ember app's rootElement, if rootElement is defined in the Ember app's config:

let App = Ember.Application.create({
  rootElement: '#ember-app'
});