Implements graceful shutdown to close #20, cleans up examples suite.

This commit adds substantial functionality in order to achieve graceful shutdowns. All shutdown functions return promises. The "tidy" function is executed as a Lua script in order to preserve atomicity.

Functions added:
* Company.shutdown
* Factory.shutdown
* Broker.shutdown
* Broker.destroyChannel
* Team.shutdown
* Dispatcher.tidy
* Dispatcher.halt
* Dispatcher.shutdown
* Dispatcher.requeueTask