Apply @uobikiemukot's patch (various pixel-format support)
https://gist.github.com/uobikiemukot/7adab29310caf0be6f7a
Swap bytes if depth == 2
Keep compatibility
Merge pull request #8 from saitoha/fix-segfault-with-introducing-various-pixformat

Keep compatibility
@uobikiemukot's patch in the conversation of #8
Merge branch 'feature-support-various-pixformat' of github.com:saitoha/libsixel into feature-support-various-pixformat
Merge branch 'master' into feature-support-various-pixformat

Conflicts:
	converters/img2sixel.c
	include/sixel.h.in
	src/tosixel.c
Merge branch 'hotfix-preventing-double-free' into feature-support-various-pixformat
Merge branch 'master' into feature-support-various-pixformat

Conflicts:
	converters/img2sixel.c
	include/sixel.h.in
	src/dither.c
	src/tosixel.c
Merge branch 'develop' into feature-support-various-pixformat

Conflicts:
	converters/img2sixel.c
	src/dither.c
	src/tosixel.c
Suppress GCC warnings
Merge branch 'feature-support-various-pixformat' into develop