The new feature makes it possible to create analytic codes for historical
data from the web interface.

Fields generated by MetaAnalytic now exclude codes with children. Fixed some issues when selecting the parent and dimension of a new analytic code. Added a new 'translate' option.

When creating a code, the parent cannot be selected (readonly) if the code's dimension is not selected (code view) or not a record in the database (dimension view, while creating a new dimension).

Added descriptions to models. Added a 'translate' option to enable/disable translation of analytic code and dimension names (default: False). Fields generated by the metaclasses now have a common placeholder string value. Cleaned up the translation file.