Previously we were checking if we should display an error message by
adding if statements in a template. This is not the best way to do
it, because it clutters a template and makes code harder to follow.
In this commit I move rendering error templates to the router. Code for
rendering error when there is no builds is not the best way to do it
either, but it can be improved when new router changes are merged to
Ember's master and a way Ember Data is handling promises is revised and
improved.
50cdc4cf98