Fix some datatypes not working with multiple Archetypes

Some Umbraco PropertyEditors rely on the ID of the property as they're doing DOM lookups on them - [example (DatePicker)](https://github.com/umbraco/Umbraco-CMS/blob/7.0.4/src/Umbraco.Web.UI.Client/src/views/propertyeditors/datepicker/datepicker.controller.js#L56)

This adds the Archetype's Property Alias (from Umbraco) to the unique ID we generate for each property we render.

*Example:*
Old: `archetype-property-0-0`
New: `archetype-property-sliderItems-0-0`

This should fix #50 and #51 

Need to DRY this up later ;)