Checking flipnote integrity

[NotImplementedLife]

Because unofficial flipnote players tend to be indulgent with the PPM format, they allow for playing spin-off flipnotes which the DSi Flipnote Studio app would delete when attempting to open them. Here comes in a built-in tool to detect whether a flipnote is being recognized/playable on a DSi. Not so useful in practice for anyone, but an interesting coding task to think about on a rainy afternoon.