Added support for contexts, as ambi wasn't able to do the introspection correctly
Updated ambi's version to support optional arguments in task methods
Turns out the introspection works fine with straight binds, the issue with chainy was due to a late bind being required
v3.4.0. Improvement.

- v3.4.0 May 8, 2014
	- Added `context` option for Task, to perform a late bind on the method
	- Asynchronous task methods can now accept optional arguments thanks to new [ambi](https://github.com/bevry/ambi) version
	- Updated dependencies