Revert "Omit some needless conditions", to fix access violations

This reverts commit 2cb46ca69a68a9eb837e0696080e27708286915c.
Improve the quality of monochrome dithering
Define and select color index #1 when monochrome sixel mode
Add some smoke tests
Update version
Enable missing -q/--quality option
Update minor version
Rebuild
Minor fix
Merge branch 'improve-monochrome-dither-quality' into develop
Merge branch 'fix-quality-option' into develop
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