catalog generation
 * fix issues with undefined values of dict/Values
 * json schema validation of requirements added
 * creating utf-8 encoded output for catalog entries
fix import error
catalog generation
 * escape html named entities
fix __str__() of Values/Entities
meta processing
 * GE uptake presenter restored
 * fix for Entity __init__ calls
 * begin refactoring of visitors
 * fix for naming conflict in Values
 * clean up of unused code