Non blocking

[s-cork]

Some updates and breaking changes updates

• async call objects now have a .result, .error and .status property
• wait -> await_result.
• tried to make the logic for on_result() and on_error() clearer by moving it to JS.
• added some client tests to the end of the module

breaking changes:

• Interval - the .interval property was replaced by .delay
  • this means that setting delay = 0 causes the interval function to run every 0 seconds
• Interval clear_interval() -> clear()

The breaking changes are there for consistency between Timeout and Interval.

I can make this backward compatible. But I think the number of users affected by these changes might be close to zero.

[meatballs]

And they were clearly warned!