[New Feature] Add option to save translated words and sentences

[StanislawStanislaw]

Translator should have possibility to save translated words and sentences in aim further learning them. User could be able to export saved words to pdf or export to quizlet app.

[gustavklopp]

I'd like to see the history of words previously searched also. For language learners, I think it would be an useful feature to reinforce your memory.