[evol] synched MilkyPond shadow config with current schema
[evol] added restriction on parents for MP objects
[evol] recognize 'root' and understand it as value (but not yet as argument), clarify the full handle format, and recognize the MP root
[fix/evol] correct a bug in the item creation when handling the parent parameter, allow specifying a default parent per object, and provides a new find_by_full_handle() handy method
[evol] limit parent location/type for item creation (not yet properly integrated)
[cleanup] reorganized config
[fix] added missing start of YAML document in MP shadow config files
[evol] added default config and simplified MilkyPond shadow config (and minor other changes)
[evol] improve config #10 (improved object definition check)
[evol] improve config #8 (shadow selection support)