Added the other maintainers. Updated the description
v6.48.1. Bugfix. Improvement.

- v6.48.1 August 9, 2013
	- Fixed [issue #584](https://github.com/bevry/docpad/issues/584)
		- Now the output filename of a file without an extension will remain unchanged
	- Added a test for the aforementioned issue
v6.49.0. Improvement.

- v6.49.0 August 9, 2013
	- DocPad will now shutdown and destroy itself more thoroughly
		- Thanks to [Ashton Williams](https://github.com/Ashton-W) for [issue #595](https://github.com/bevry/docpad/issues/595)
	- Added the event `docpadDestroy` for plugins that are doing anything long-running so they can destroy themselves thoroughly too
removed helen as a maintainer, added chase to contributors
fixed date of last release in changelog