Updated set and plugin lockedAtrributes methods

- lockedAttributes object now enables lockedAttributes that the model
will only set once it’s validated that all plugins want this attribute
to change
- Waits until ``’app:dataReady’`` event is called before checking.
- Triggers ``’invalid’`` event if no pluginName is passed in the
options argument that passes out the model and validationError
- syntax for these lockedAttributes is now
``model.set({‘_isVisible’:false}, {pluginName:’_trickle’}]);``