+ (0.5) attributes with value generated by sequence
- use grid for attribute list in entity (maybe grid will be more general)
- fix size problems when displaying texts in schema
- fix printing of schema (multi-page)
- some indexes can be automagically generated by DB "system" - eg. unique index for primary key in pgsql
	call server-dependend methods for such activities
- models = named parts of schema
	- use drag-and-drop for inserting entities into a model