Removing concept of "picker restriction" in AbstractPickerDataTransformer and replacing with "max selections"
Removing concept of "picker restriction" in AbstractPickerType and replacing with "max selections"
Updating usage of picker restriction constant and replacing with max selection value
Adding assertions to ensure max_selections option adds data attribute
Removing AbstractPickerType::buildView(), and dependency on decorators as they are no longer needed (transformers will eventually output JSON for select2 client-side integration)
Removing unused 'use' statements
Updating MockEntity to support "name" property
Updating tests for AbstractPickerDataTransformer
Updating AbstractPickerDataTransformer and extending classes so that they support the transformation of objects into JSON strings
Updating UserPickerDataTransformer tests to assert new functionality of transforming entities to simple objects
Updating ClientPickerDataTransformer tests to assert new functionality of transforming entities to simple objects
Removing redundant code in test
Adding test for null "max_selections" value
Merge pull request #99 from tickit-project/feature/picker-max-selections

Updating Pickers to support select2