Reworked the tank a bit

*changed how it sends packets to only update if something changes or at
random points in time.
*changed the getColor() to use the blocks metadata and not a var
*added code to the setColor to change the blocks metadata
*Fixed load function to not set content if it read as unkown
added code for setColor() to pipe

as well caught myself on the setColor() function for the tank were i
left out the ! in from of the check for client.