[Grok-doc] Review - REST support in Grok

[Paul Wilson]

Hi,

I've made some small modifications to the broken document concerning
Grok REST support:

http://grok.zope.org/documentation/how-to/rest-support-in-grok
https://blueprints.launchpad.net/grok/+spec/doc-rest-support-in-grok

Summary of changes:

 * Fixed the example to use 'grok.restskin()' rather than RESTProtocol
 * Modified the wording to refer more to rest skins rather than rest protocols
 * Added an example of applying a skin upon traversal.

I would very much appreciate somebody reviewing the revised version.

Regards,
Paul