Make TNMAide UI more intuitive

[AaronHastingsVolpe]

Everything is correct in the UI as is, but it is a little confusing. I think it would be better to require at least one table (either Ldn or Lden) to be filled in. Then compute for each table that is filled in. I.e. if only Ldn table is filled in, just compute Ldn. If only Lden is filled in, just compute Lden. If both are filled in compute both. In this case on a simple button that says compute is needed.

It would also be good to flash a red warning (even just saying see the log) if an error is thrown.