Precompile defaultTemplate even in development versions.

Currently Handlebars strings in Ember core are precompiled
into functions in `dist/ember.prod.js` and its derivatives.

Except for cases where ember itself uses these strings
developers using a build tool in development could use
handlebars-runtime as a dependency.

The only instance of Handlebars string templates in Ember
is the defaultTemplate for Ember.Select.

This moves the precompilation process earlier in the pipeline

One goofy side effect: documentation examples for defaultTemplate
will also be compiled.