Unified data types [actualType and subType]

Updated tests.

JMS parsing fixes; updated {Validator,FormType}Parser, FOSRestHandler, and AbstractFormatter, and updated DataTypes enum.

Modified dataType checking.

Updated tests.

Updated DataTypes enum.

Quick fix and added doc comments.

CS fixes.

Refactored FormTypeParser to produce nested parameters. Updated tests accordingly.

Logical and CS fixes.

Sub-forms and more tests.

Ignore data_class and always use form-type to avoid conflicts.

Quick fix.

Replace #414
It does not break the sandbox, since `AbstractFormatter` will still flatten this into `collection_type[a]` and not `collection_type[children][a]`. This is asserted throughout `MarkdownFormatterTest`.