Improved support for translations of songs

[aspettl]

Use case: Have songs only once in the library with e.g. English as primary language and German as secondary. Use one song file for the scenario "show English & German" as well as for "German only".

Current situation: So far, one can only swap song text and translation at runtime. This information is not stored and lost as soon as one switches to another song.

Proposed changes:

• Do not only allow to swap text and translation, but also provide the possibility to use one of them only. Introduce a new dialog window for that.
• Store the selection into the options in the portfolio file (options exist already for video files to select start and end time)
• Mark portfolio file as changed when options in the portfolio file change (also for videos).
• Introduce CCLI number for translation, adjust report to SongSelect accordingly.
• Fix issue where enabled state of the switch translation menu item was incorrect depending on focus (always disabled when not in song panel).

Compatibility: Older versions of WordsLive can still open the files saved with this version. The new options are just ignored in that case.

This should resolve https://github.com/Boddlnagg/WordsLive/issues/12 and https://github.com/Boddlnagg/WordsLive/issues/3 and is also related to https://github.com/Boddlnagg/WordsLive/issues/13.

[Boddlnagg]

Thank you very much! This is a great improvement.