hookbox updates: additional parameter for HookboxProtocol.onSubscribed

[Dax]

Hi All,

This update allows the web application to provide the initial data on
a successful channel. Removed the unused CHANNEL_INIT message in the
process. The web application should return a json data similar to
below (replace initial_data_here)

[true, {'initial_data': initial_data_here}]

and then you can put additional client side processing by providing
logic on (web) socket connections onSubscribed function (note: NOT the
subscription.onSubscribe function).

latest code: https://github.com/hookbox/hookbox
documentation: http://hookbox.readthedocs.org/en/latest/index.html

Regards,
Dax