Added AJAX control for getting Tag names to apply
Additions:
- NuGet AJAX Package
- TagService.asmx: Web service to service AJAX controls

Changes:
- Web.config: AjaxControl toolkit added
- Site.master: Changed over to AjaxControlToolkit script manager
- packages.config: Added AjaxControl Toolkit
- MovieDetails: Added Ajax Control for a dynamic drop down menu to select an existing tag name
- Tag.cs & TagFromQuery.cs: Moved TagTypeEnum into Tag.cs.
- MovieActions.cs: Added a query for a list of tags by a categoryID for the TagService