adding a test scenario
empty helpers shouldn't insert child elements.
making `use` semantics depend explicitly on initial render
changelog for `use` semantics
new containerless option
use containerless to simplify liquid-modal
beefing up flexbox scenario
unit tests for containerless
only append modal component if modals are configured

Closes #70
Use `needs` to avoid instantiating the application controller too early

Related to #69
implement containerless with the real Metamorph mixin

The previous hack doesn't work.
more graceful initialization of modals
Prevent test/demo app config from leaking into consuming app.

As of Ember CLI 0.0.45 and up, the file located at
`config/environment.js` will be used to return the addon's own
configuration.  That conflicts with the way this library is using
`config/environment.js` (for the testing/demo app).

This simply overrides the default config hook to return nothing.
Merge pull request #75 from rwjblue/do-not-leak-config

Prevent test/demo app config from leaking into consuming app.
closes #77
releasing
adding nested outlet scenarios
speed up acceptance test animation
nested outlet support

Closes #41.
Closes #83