Fixed DvdTitle Property

Property incorrectly used the _dvdTitle Member, rather than value when
checking to see if the dvd title is blank.
Automatically generated code
Added Validation Methods

Created the skeletons for all validation methods.
Added validation for chkBluRay, dtpPurchaseDate, rdoCategories,
txtDvdTitle.
Created the skeletons for txtLengthMinutes and txtPurchasePrice KeyPress
methods