Pipe command

 From:  Michael Gibson
4309.2 In reply to 4309.1 
Hi Felix, yeah I'd like to improve that in the future.

Right now the way that Pipe works is that it internally kind of acts as a coordinator for a number of other commands like circle, sweep, and boolean difference. The "calculating" UI mechanism is not right now set up to display in this case where a command is actually made up of a number of sub commands like this instead of it having a single constructor object.

- Michael