refactor+fix submit/verify disc id

[JonnyJD]

Clean up after implementing #14

submit should be renamed to verified in most places or similar. It is all about verification, not about whether we want to submit at all. The user decides if he wants to submit in the end.

[JonnyJD]

While refactoring I realized: d7f0d96 actually broke recalculation.

Another reason why refactoring is good ;-)