override puts
Add thread safe way of removing multiple handlers
at the end of an arbitrary handler fn.

* To remove the current handler return :remove_handler
* To remove an arbitrary handler return [:remove_handlers,
                                         [handle, key]*]
Prefix non-public API functions with __ 

This indicates that they should probably be in a
separate object...
Add state lifecycle information to nodes:

* :pending   - node has been created in Sonic Pi
               but not yet on the server
* :live      - node is running on the server
* :paused    - node is paused on the server
* :destroyed - node is no longer on the server