More music to choose from

Nobody has claimed this yet.

In addition to the "Trial" and "Pursuit" tracks, I thought it might be nice to potentially have cross-examination and objection themes play. My branch [cross-examination-music](https://github.com/Meorge/objection_engine/tree/cross-examination-music) currently has:
- *Cross-Examination ~ Moderato*
- *Cross-Examination ~ Allegro*
- *Trial* (`trial.mp3`)

as "relaxed" tracks (that play at the beginning of a clip), and
- *Phoenix Wright ~ Objection!*
- *Pursuit ~ Cornered* (`press.mp3`)

as "tense" tracks that start playing after an Objection.

This is sample output from it, showcasing the different themes:

https://user-images.githubusercontent.com/9957987/201011340-2d062f61-31d9-4eca-bf9e-57fa4008d1a6.mp4

Unfortunately, right now it switches the "tense" track every time there's an Objection... that's (probably) something I'd need to fix, because otherwise in a heated conversation it might keep switching between tracks really quickly. Shouldn't be too hard of a fix, though - probably just has to do with reworking how the `if last_audio != new_audio` logic around line 550 of `anim.py` works a little bit.

Start in anim.py around line 550, especially the `if last_audio != new_audio` logic, and review the cross-examination-music branch for the existing track setup. Verify the relaxed and tense themes can be selected as described, and that repeated Objections do not switch tense tracks rapidly.

Written by the indexing model from the issue text.