I'll add a few directives to facilitate automated generation of documentation by rdoc, and, following @natacha-beck suggestion, move the property table into a separate file

Tested with rdoc 6.6.2, please check now @prioux @natacha-beck

So I understand that adding comments in the BoutiquesSupport module was made difficult because many classes, instead of being declared like the standard:

class BoutiquesDescriptor < RestrictedHash
end

were instead declared with meta programming, as in:

BoutiquesDescriptor = Class.new(RestrictedHash) do
end

So the RDOC parser couldn't really identify what methods were in which class.

Well, I solved that problem by modifying boutiques_support.rb and re-coding all the declarations
in the standard way!

The commit for my change are in master and can be seen in

bde0844

Please rebase to master, take the documentation in this PR and just move it to their proper methods, in
the standard RDOC way. It could be easier to just start with the master version of the code and
re-introduce the comment blocks one by one, because otherwise there will be tons of merge conflicts.