1.0.6.4

### Bug fixes: * Fix coin selection label filter (@Kukks) * Greenfield: Fix behaviour after first admin signup (see #2150) @dennisreimann * Greenfield: If invoice is not found, error 404 should be returned rather than a crash @dennisreimann * Attempt to fix sometimes broken Mark as Seen button @NicolasDorier ### Improvements * Improve the invoice details view (see #2144) @dennisreimann @dstrukt ### Miscellaneous * API Keys: Add usage examples link to docs @dennisreimann