Palette generation for SNES is broken as of commit 9236a2a

[CataLatas]

As the title says, commit 9236a2a appears to have broken SNES palette generation.

Running a basic test against the previous commit (cbef58a) with the command superfamiconv palette -W16 -H8 -P1 -C16 -R -i testinput.png -j testpalette.json, I get the following results:

Bad palette JSON (commit 9236a2a):

{
  "palettes": [
    [
      "#000000",
      "#424200",
      "#000039",
      "#84007b",
      "#18d600"
    ]
  ],
  "palettes_native_rgb": [
    [
      [
        32,
        0,
        32
      ],
      [
        8,
        8,
        32
      ],
      [
        32,
        0,
        7
      ],
      [
        16,
        32,
        15
      ],
      [
        3,
        26,
        32
      ]
    ]
  ]
}

Good palette JSON (commit cbef58a):

{
  "palettes": [
    [
      "#ff00ff",
      "#4242ff",
      "#ff0039",
      "#7bff7b",
      "#18d6ff"
    ]
  ],
  "palettes_native_rgb": [
    [
      [
        31,
        0,
        31
      ],
      [
        8,
        8,
        31
      ],
      [
        31,
        0,
        7
      ],
      [
        15,
        31,
        15
      ],
      [
        3,
        26,
        31
      ]
    ]
  ]
}

The test input image is the following:

To me it looks like it's erroneously rouding up the 255 (31) color values to 32.

I haven't checked other modes except for SNES.