[BlueBream] Third part of tutorial: skinning

[Baiju M]

Hi,

Oh. yet another issue with skinning :)

The skin is created from scratch. But this is not very practical.
Because many basic view registration will be missed.

Again more choices:-

1. Use z3c.layer.minimal (not yet part of BB)
2. List those registrations in doc so that user can copy paste it.
3. Include the basic registration in project template
4. Create a new package to scaffold the skin package
    which include these registrations.

I am going for the second choice for now. I will also mention about
z3c.layer.minimal package there.

Please let me know your suggestion.   I feel writing this documentation
is like telling a good story.  Sometimes I adjust the code to make the
story better.  But for some cases we need to change our approach itself
or change the package implementation or go for a better package.
Also we need to keep a balance between simplicity & practicality.

Regards,
Baiju M