Documentation

Hi there.

I like this component and would like to use it, however I find it difficult to achieve a couple of things without documentation:
- how to silently wait for "minimum search length" as on Demo page? I try to return empty array in the action:

``` javascript
search: function(term) {
if (term && term.length >= 3) {
return new Ember.RSVP.Promise((resolve, reject) => {
...
});
} else {
return [];
}
```

but obviously I see "No results found" below the text input while the length of the search is less than 3 symbols.

Start with the Demo page and the search action shown in the issue, then trace how the component displays results while the term is shorter than three characters. Document the minimum-search-length behavior and the expected empty-state behavior, using the existing documentation location identified in the repository.

Written by the indexing model from the issue text.