Issue #5: Completion of error handling
Merge branch 'fix-issue-5' into release-1.1
Update version
Fix for some environment missing "getopt_long"
Merge remote-tracking branch 'origin/hotfix-for-env-missing-getopt_long' into release-1.1
Fix Issue #6: Remove unnecessary null pointer checks
Remove original sixel (kmiya's sixel), Mirror repo is now here:
https://github.com/saitoha/sixel
Merge branch 'fix-issue-6' into release-1.1

Conflicts:
	converters/img2sixel.c
Fix a regression bug introduced by 0221665
Merge branch 'fix-issue-6' into release-1.1
Merge branch 'develop' into release-1.1
Fix a compile error
Fix a compile error
Merge branch 'fix-issue-6' into release-1.1
Merge branch 'release-1.1'