document the return value of the filter() method. RT #72369

document i_gsamp_bits() and i_psamp_bits(). RT #68815

properly increment the Imager::Matrix2d $VERSION.

actually include the Imager::Test tests in the dist

correctly read and write 256x256 pixel ICO files RT #69599

make the error message from read() or read_multi() when they can't identify the file type match reality. RT #72475

read() now uses $FORMATGUESS if it can't determine the file type link based on the file header, to match read_multi().

re-work and add tests for def_guess_type(). def_guess_type() no longer returns any random file extension as the file type.

add gray4, gray16 and gray as presets for make_colors. RT #67911

add make_palette() method that produces a palette from one or more images.

fix the Imager dependency for the separately distributed font drivers. RT #72643