Finish relations questions

[slaweet]

• [x] Add field "additional info" to flashcards.
• [x] Change "Practice all" to exclude relations questions.
• [x] Don't allow to answer with the term in question
• [x] Make relations questions accessible from the menu
• [x] Beta test
• [x] Fajfka
• [x] Missing image message
• [x] English in Latin terms
• [x] All questions are green in summary
• [x] Remove getConfig("proso_flashcards","practice.common.
• [x] Typeahead duplicates
• [x] Highlight answer