Added pin to drive wheel
Added animation to the drive wheel
Added calculated x/y position of the drive pin

To be used later to determine the rotation of the wheel.
Added logic to detect when pin is within the wheel
Added dynamic rotation to the wheel

Wheel position is now linked to the position of the drive pin.
keeping spin angle value in 0 to 360 range
fixed incorrect slot depth
Added directive for binding SVG viewBox attribute

Fixes #1