Disable ember-dev's clearing of Ember.TEMPLATES.

`ember-dev` currently clears `Ember.TEMPLATES` after each test run. This
will be fixed in `ember-dev` with https://github.com/emberjs/ember-dev/pull/96.

This is a temporary fix until that PR is merged.
Merge pull request #62 from rjackson/fix_builds_temp

Disable ember-dev's clearing of Ember.TEMPLATES.