typehead open when input focus

typehead open when input focus
```
<div class='container-fluid'>
    <pre>Model: {{selected| json}}</pre>
    <input type="text" ng-model="selected" typeahead="state for state in states | filter:$viewValue" typeahead-min-length="0">
</div>
```
Forked from https://github.com/zacronos/bootstrap.git and edited.