Added delta byte and slider, fixed labels for sliders

Packet structure is now
Header(0xff),X(High), X(Low), Y(High), Y(Low), Z(High), Z(Low), Wrist
Angle(High), Wrist Angle(Low), Wrist Rotate(High), Wrist Rotate(Low),
Gripper(High), Gripper(Low), Delta(Low), Button Byte, Extended Byte
Patched button values into the serial packet

Before we were just sending a '0', now we'll actually send the button
value.
Also fixed a bug where the button checkboxes didn't update the value
correctly (needed to reset buttonByte to 0 during each update cycle)