bibleBooks.txt CSV file remains largely unchecked

[skreutzer]

No or little checking takes place for the bibleBooks.txt CSV file. If the file gets modified by the user. A trailing newline at the end of the file or missing CSV fields would cause IndexOutOfBoundsExceptions without a hint that a bad bibleBooks.txt file caused the problem. The program might skip incomplete lines and just give a notice, or abort program execution. I think this issue is of low priority as users aren't expected to modify bibleBooks.txt all too often.

[schierlm]

As we now have a --book command line option, I cannot think of any use case for manually editing bibleBooks.txt file. Especially since editing that file will also break cross references to other books.

[patrickbkr]

For the sake of being nice to our future selves that have to debug an error by modifying bibleBooks.txt I do not object some error checking code. PRs welcome!