Reimplemented cases for soundfiles where _lex or _pron is necessary.

- This is to deal with #17, but I'm not confident enough of the outcome to close it.
  Instead I'd like to build a script that checks all soundfiles,
  and informs about the mismatch as two tables.
  One such table shall be for existing soundfiles that are not found,
  and one for 'found' soundfiles that don't exist.
- Also fixed a JavaScript bug stemming from "use strict";