Fixed sql92 definition, added generating foreign keys code

Fixed sql92 definition json. Added generating foreing keys code for each
table that contains foreign key. Changed relation model to contain
fk -> pk columns mapping instead of separated fks and pks columns ids.
Added dialog for generated sql, setting title for relation and table dialogs
Added extending of defs, routes test, grouping of data types

Database definitions can extend another definition. Fixed db definitons
(type exactly). Added base for routes testing. Column's types grouped by
its type (according to sql specification).