Update README.md
Add use case test for issue #80
Add force single line setting, default to False
Correctly handle force_single_line from within Import Sorter
Add -sl, force_single_line option to command line tool
Add documentation for new output mode
Merge pull request #82 from timothycrosley/feature/fix-issue-80

Feature/fix issue 80
Bump version to 2.6.0
Merge branch 'release/2.6.0'