[evol] artworks context menu: finished mechanism + checked for empty selection + implemented associate_with_tag action
[evol] preliminary artworks context menu (reverted license to GPL2+, to be compatible with Proto.Menu and possibly other plugins)
[evol] added tags and fixes a few typos
[fix] renamed 'technique' into more appropriate name 'artwork_support', and update schema and translations (Closes #4)
Initial version