Merge branch 'develop' into release-1.3
Merge branch 'hotfix-for-paletted-png' into release-1.3
Bump version
Merge branch 'release-1.3'
Add some tests
Enable some options(-f, -s, and -q) ignored unintentionally
Merge branch 'hotfix-for-disabled-options' into develop

Conflicts:
	converters/img2sixel.c