Read correct color from ILDA files

[SpaceK33z]

At the moment the colors from an ILDA file can only be the pre-defined ILDA colors (a list of 65 colors).

If an ILDA color table was added (format 2) to the file it doesn't pick a color out of that.

The most spec-compliant way to deal with this is that the point should have a color property which points to the index of a possible custom color, and if none have been given, one of the ILDA color list is used.

However, I want this library to be easy to use and just get the correct rgb value. Maybe I should add an option to switch between this?