Implement custom header support.
Bump version to 0.6.0.
Reformat the Passenger docs.
Reformat the client example.
Adjust the layout of operations in API#initialize.
Move the :open driver listener to be the first one registered in Client, so status and headers have been set before other :open listeners are triggered.
Change a variable name in the examples.
Set status and headers on error, not just on open.
Remove path to websocket-driver from gemspec.