[ALOY-265] & [ALOY-266] Picker improvements in XML

#### Tickets

* [https://jira.appcelerator.org/browse/ALOY-265](https://jira.appcelerator.org/browse/ALOY-265)
* [https://jira.appcelerator.org/browse/ALOY-266](https://jira.appcelerator.org/browse/ALOY-266)