Better lexem cloning: copy meanings, meaning tags, meaning sources, synonyms,
and most Lexem fields.


git-svn-id: http://voronet.francu.com/repos/DEX@957 8d550267-2627-4c68-899f-85492a8dd5ca
When merging two lexems, join their meaning trees.
When deleting a lexem, delete its references in the Synonym table.


git-svn-id: http://voronet.francu.com/repos/DEX@958 8d550267-2627-4c68-899f-85492a8dd5ca