feat(select): Add support for select[ng-model][ng-options]?

Differences from AngularJS:
1. Doesn't support required attribute.
2. If the model is set to a value without a corresponding option will always
   add and select <option value="?"></option>
3. null is treated like AngularJS treats undefined.
4. ng-options is limited to simple list form (<expr> for <var> in <list expr>)
feat(select) Fix spec tests.