added eachCollection and eachBlock convenience methods
renamed emitSync calls to their new emitSerial name
Swapped out synchronous file system calls for asynchronous ones - close #538
fixed regression in a25c2b82ccd8a6c5da04d2d1839a8c7e9fdde6f0
v6.42.3. Improvement.

- v6.42.3 June 26, 2013
	- Swapped out synchronous file system calls for asynchronous ones
		- Closes [issue #538](https://github.com/bevry/docpad/issues/538)
	- Fixed DocPad version number undefined in X-Powered-By response header
	- Added the ability to turn off the X-Powered-By meta header by
setting the `poweredByDocPad` to `false` in your configuration