I was making a bad assumption:
1. Songs with branches have the same number of balloons.
2. Each balloon has the same number of hits across branches.
Because I was making these assumptions, I thought I could just repeat
the `BALLOON:` field for each branch. **But this is wrong!!** Branches
can have different numbers of balloons, and they can have different
number of hits in their balloons. So, we need to **NOT** necessarily
repeat `BALLOON:`, and instead use the written value of `BALLOON:`
directly. This way we can get the different values for each branch.
This fixes the parsing of Emma's Ura (and probably other songs). Also,
this revealed a bug in my parsing of Roppon no Bara to Sai no Uta, so I
needed to make sure we account for "duplicated" balloons too, and repeat
the values _only when necessary_.
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