Circular Reference/recursive node error
>> Manually reove the circular references

Element cannot be mapped to anything in mapping editor (= no data type in generated cmf), even though data type "string"
>> ABCDify xsd:
- change name space of root xsd to schema namespace
- add elementFormDefault="qualified" attributeFormDefault="unqualified" 
- add xmlns:xs="http://www.w3.org/2001/XMLSchema"
- add "xs:" prefix to all data types/tags that cannot be found now (use search/replace)

Error "global type cannot be found"
>> Open structure_handler.py, method resolveRefsAndTypes and replace unknown data type with some known "string" data type

Element cannot be mapped to anything in mapping editor (= no data type in generated cmf), but they're an "attribute group"
>> Not supported by current cmf_generator, this requires adding more functions :/