Merge pull request #88 from ckeditor/t/75
Other: Removed the `contextualtoolbar.scss` sass file. Converted the `ck-editor-toolbar` mixin into a class. Closes #75.
BREAKING CHANGE: The `ck-editor-toolbar` mixin is no longer available. Please use `.ck-editor-toolbar` class instead.
BREAKING CHANGE: The `ck-toolbar__container` class has been renamed, use `.ck-toolbar-container` instead.