Merge pull request #315 from D0d0/master

Added sk-SK translation and fix rowStyle
Update README.md
Modify the scope of the column events.
Fix #160, #323: operate events don't work in card view.
Add check and uncheck methods.
Update README.md
Fix #316: add 'btn-group' class to Columns toolbar.
Update usage.md
Update translations.md
merge