Suppress gdk-pixbuf assersion on processing some GIF images, reported by
@ttdoda
Merge branch 'master' into fix-suppress-gdk-pixbuf-assersion
Merge branch 'fix-suppress-gdk-pixbuf-assersion' into release-1.2
Bump version
Fix wrong HLS-to-RGB conversion routine
Merge branch 'release-1.2'
Update README and ChangeLog
Merge branch 'release-1.2'
Merge branch 'master' into develop
Update usage
Add new API, sixel_dither_set_body_only
Merge branch 'feature-verbose-mode' into release-1.3
Merge branch 'feature-omit-palette-definition' into release-1.3

Conflicts:
	src/tosixel.c
Merge branch 'fix-wrong-hls-to-rgb-conversion' into release-1.3