Add filter to guard

Add an optional filter parameter prefix to prototype.guard, see api doc.

Add throttle, change parallel and sequence implementation

Add throttle, change parallel and sequence implementation.

Split ajax related stuff into ajaxHelpers.js

Split ajax related stuff into ajaxHelpers.js

Make go default to id function

Make prototype.go default to id function, now you don't have to supply id function if you when you compose functions using Action.

Add Action.signal

Add Action.signal, a very kind special Action. also some examples.

Add context support inside continuation

Add context support inside continuation, you can now use this to refer the Action instance inside continuation when you constructing an Action.

All combinators return cancel handler now

All combinators return cancel handler now, check out wiki.

Fix a bug of Action.parallel

Fix a bug of Action.parallel, add test

Action.co stablized

Action.co stablized, doc up to date

Remove gapRetry

Update document, remove gapRetry since it's just retry compose delay.