More animation tweaking.
Implemented the library tab with grouping. Updated viewer to accept ChapterLight.

Grouping/Sorting references:
http://karlshifflett.wordpress.com/2009/06/10/wpf-sample-series-listbox-grouping-sorting-subtotals-and-collapsible-regions/

http://msdn.microsoft.com/en-us/library/system.windows.data.collectionviewsource.sortdescriptions.aspx