Change in format specs for version 2.0

[stefanoborini]

Potential changes to accommodate PR #121:

• [ ] remove the distinction between fixed vs variable properties. We will have instead two classes properties: (CUBA) properties and support properties. CUBA properties MUST be referred with the fully qualified key, and (as normal) the key must be defined. support properties are special names that are not CUBA. We should only have one: parent
• [ ] introduce a key in the CUDS entry to specify that a given property is readonly.
• [ ] solve the problem when properties must refer to cuba keys, rather than objects (e.g. variables must be a type CUBA.VARIABLES, and each of them must be a CUBA key). same for models (it must be a list of CUBA keys, not a list of instances)

In addition, we should

• [ ] unify cuba.yml and simphony_metadata.yml

[stefanoborini]

Note: this is still a matter of discussion and will probably change.

[stefanoborini]

Closing. We are moving away from the YAML representation