"Indexed colors without a palette" for indexed image that has a palette

[KeyboardDanni]

Asefile does not seem to think that this indexed color image has a palette, even though it has a full 256-color palette stored in it. Here's what it looks like in Aseprite:

For some reason this gives Invalid Aseprite input: Indexed colors without a palette

The source .ase file (had to zip this or Github wouldn't let me attach it):
animation_tracks.ase.zip

[KeyboardDanni]

It appears that Aseprite is saving only the old style palette chunk (0x0004) and not the new one if there are exactly 256 colors in the palette. According to the documentation on the file format:

"Ignore this chunk if you find the new palette chunk (0x2019)"

We aren't finding the new palette chunk in this file, so we should be using the old palette chunk to populate the palette data.

[KeyboardDanni]

Wrote a fix for this in #13

[alpine-alpaca]

I merged Pr #13 and released it with v0.3.4.