v6.52.2. Bugfix.

- v6.52.2 September 16, 2013
	- Possible fix for `Error: A task's completion callback has fired when
the task was already in a completed state, this is unexpected` error
		- Thanks to [Ryan Fitzer](https://github.com/ryanfitzer) for [issue
#643](https://github.com/bevry/docpad/issues/643) thanks to
		- Thanks to [drguildo](https://github.com/drguildo), [Evan
Bovie](https://github.com/phaseOne), [Brandon
Mason](https://github.com/bitmage),
[ashyadav](https://github.com/ashyadav) for [issue
#623](https://github.com/bevry/docpad/issues/623)
	- Will now output the progress of `iconv` install if `detectEncoding`
is true and `iconv` isn't installed
	- Updated dependencies