Add invert option
Fix typos: sence -> sense
Update manpage and README
Fixup for correcting getopt option
Assume default SIXEL palette as fore-color
Merge branch 'assume-default-palette-as-forecolor' into feature-invert-option
Fixup for the effect of invert option
Update version
Rebuild
Merge branch 'release-0.17' into develop
Merge branch 'develop'