Uninstall WPFToolkit. Change control template of toggle button used for
BoardLocation

Not sur why the WPFToolkit was installed. It's now removed. Board
locations are now selectable. A red border appears upon MouseOver and
selection. When a BoardLocation is disabled, there won't be a change in
visuals - that functionality was removed by overriding the control
template.
Fixed issue with BoardLocation selection visual.
Pieces exist.

The chess board is now initalized with all of the black and white pieces.
These pieces are currently represented as strings on the board. It will
change to images eventually.
Piece heirarchy. Movable pieces.

Instead of enumerating piece types I decided to create a heirarchy.
There's now a rudimentary piece moving system in place. There's a visual
glitch with selecting boardlocations but I'm fairly sure I know exactly
what's wrong.

Instead of defining the togglebutton control template in a style the
template is defined as it's own key. The datatemplate of boardlocation is
now defined in ChessBoardView.xaml.