Update CONTRIBUTORS.
Update CONTRIBUTORS.md
Update CHANGELOG.
Make optgroups' checkboxes optional
apply more accurate name for option
New options: displayValues and delimiter
Merge pull request #98 from brettz9/copy-select-and-options-classes-to-list

If a class is present on the original <select> or individual <option>s, ...
Merge pull request #100 from brettz9/connect-select-back-to-its-label

Connect select back to its label to fix issue #99
Merge pull request #101 from brettz9/optgroup-checkboxes-optional

Make optgroups' checkboxes optional
Merge branch 'master' of https://github.com/wenzhixin/multiple-select.git into brett-demo