Please include (Hunspell) dictionaries
As far as I understand, Nimbus only supports American English for spell checking. To support other languages like British English or German, please support dictionaries. Hunspell
would be a good idea I think, if you just add the option to add Hunspell dictionaries via their URIs (also file:// for local ones), and to select the dictionary to be used as default and optionally for each note.