Improve README
Improve README

* Add a note about being in early development
* Add a link to uri-templates (for credit and documentation reference)
* Note requirements on recent ember-data changes
* Give some examples of `findQuery` support

amiel/ember-data-url-templates,bcardarella/ember-data-url-templates,amiel/ember-data-url-templates,bcardarella/ember-data-url-templates