Schema 5.4 does not work

[dirk-qualisys]

A user pointed out that the type PhraseId is missing in the latest release and thus the schema does not work out of the box.

Long story short: As the QA measures taken in earlier releases are not necessarily applicable for timing constraints, and have not been applied to validate the 5.4 version, we need a procedure to validate a schema (not XML file). See also

• https://stackoverflow.com/questions/28414582/how-to-validate-the-xsd-file-itself
• https://stackoverflow.com/questions/3996743/xml-schema-to-validate-xml-schemas

and then some bogfix to the schema. I will work on this but are happy for any hints.