[Grok-dev] 'jw-simpler-skin-registration' branch ready for merge

[Philipp von Weitershausen]

I took the liberty of finishing JW's 'jw-simpler-skin-registration' 
branch. It now allows you to define layers and register skins like this:

   class IMyCustomLayer(grok.IBrowserRequest):
       pass


   class IMyNiceSkin(IMyCustomLayer, grok.IDefaultBrowserLayer):
       grok.skin('Nice Skin')

I have not done anything about the old way of registering skins (using 
this grok.Skin class). It's still in there and works, without any 
deprecation warnings.

What shall we do with it? We used to be ok with breaking 
backwards-compatibility in Grok since we're still in 0.x. Is this still 
the case? Do we need a deprecation period? Shall we send deprecation 
warnings?


Personally, I favour ripping it out altogether and having decent upgrade 
notes, as we did with all backwards-incomaptible changes before.

Thoughts?