Added Inventory slot selection.

Signed-off-by: Jacob Duddles <jacob.duddles@live.co.uk>
Added stuff.

Signed-off-by: Jacob Duddles <jacob.duddles@live.co.uk>
Added Inventory item addition and subtraction

Signed-off-by: Jacob Duddles <jacob.duddles@live.co.uk>
Signed-off-by: Jacob Duddles <jacob.duddles@live.co.uk>