finish implementing selection
finish implementing selection

There is still an issue where the arrow up/down key are pressed and
shift is held. Will fix.

hachidorii/JNWCollectionView,konstantinpavlikhin/JNWCollectionView,kettch/JNWCollectionView,danielmartinprieto/JNWCollectionView,jwilling/JNWCollectionView,chriseidhof/JNWCollectionView,regexident/JNWCollectionView,Spark-Xl/JNWCollectionView,Deadpikle/JNWCollectionView