Fixes ENYO-653

## Issue
The documentation for `enyo.Model.fetch()` states you can pass `parse: true` as an option and the data returned will be sent through `enyo.Model.parse()` once the fetch completes ... It doesn't.

## Fix
Check for the option and `parse()` when requested. Thanks @kurthong!

## Note
Supplementing PR #944 with a mocha test and some clean up.