Fix endian dependent color reading

[Eathox]

Issue

When reading the HEX colors from a xpm42 file strtol is used over the whole HEX sequence, strtol treats this whole sequence as one number. Therefor when the endian doesn't match the presumed RGBA order the result is not the expected color.

Sample image with incorrect endian:

Solution

Instead of using strtol over the whole HEX sequence, use it only over the individual color channels and then manually bit shift the channels to the expected location.

Sample image with HEX channel correction:

[W2Wizard]

Looks all good! Thank you 👍