Clean up JSHint integration and code

* exclude 3rd-party libraries
* fix all remaining warnings
Make ConnectionManager handle XHR activity checks
Refactor transport hierarchy
Add TransportConnection specs and fix broken ones
Add specs for all transports and remove old ones

* remove unnecessary transport names
* fix minor glitches in Pusher.Util.isX(H|D)RSupported
* change the onOpen hook to beforeOpen
Refactor timers into a single file
Refactor Connection class internals
Remove wssHost and httpsHost options
Don't send the log level in timelines
Fix Flash specs failing on IE6-8
Document the transport code.
Add staging CDN to config.yml.example
Refactor loading script files

* DependencyLoader now calls back on failures
* JSONP and DependencyLoader share script code
* change the way URLs, tag ids and callbacks are generated
* update all dependants of modified classes
Change ScriptReceiverFactory interface

* add a number field
* register callbacks as Factory[number] rather than Factory.id
Add specs for ScriptReceiverFactory
Don't bind MozWebSocket to WebSocket anymore
Move jsonp/jsonp_receiver.js to jsonp/jsonp.js
Update specs for JSONP
Add integration tests for ScriptRequest
Move the ScriptRequest receiver to the send method