Add a copy button and save word context (off by default), shown
via the three-dot menu of word entries.
Also some db refactoring and minor UI improvements:
- a dedicated book title table in order to shrink db size by storing
references to title names instead of repeated actual strings,
- alignment of different forms of the "more" button and possible
clipped words in translations.
- fix plugin name so it can be disabled
cafbf36bb2