Draft: F json specification doc

This branch enhances the documentation with an annotated and referenced cfood yaml schema.

This is currently a proof of concept.

Still todo:

• doc/ will become the main location for the schema.
• Add references and descriptions of the schema in the docs.

requested review from @henrik

assigned to @salexan

mentioned in issue #65

changed the description

added 104 commits

• 3ca144bd...0bdf4ed0 - 101 commits from branch dev
• 41a8de9d - Merge branch 'dev' into f-json-specification-doc
• d5456118 - duplication and out of date
• 3e0e3e82 - WIP: add explanation

Compare with previous version

I added an explanation and removed the additional "cfood-schema.yml" and replaced it by a symlink (having two files seems to be a bad idea and I think the schema may reside with the sources).

@salexan What else would you like to do here?

I think, the schema.yml-document should be turned into something more readable. I will have a look at it.