Make Seven theme's link + button focus styles more robust for keyboard accessibility

(See comment #16 for some hints on what that comment can say.)

The initial commit already included a file with the following content.

/**
 * @file
 * Seven specific styling for CKEditor admin.
 */

/*
 * This rule is needed to provide Seven's blue focus outline.
 */
.ckeditor-toolbar-disabled .ckeditor-buttons li a:focus {
  box-shadow:
    inset 0 1px 3px rgba(0, 0, 0, 0.05),
    0 0 8px #40b6ff;
}

.ckeditor-toolbar-active .ckeditor-buttons li a:focus {
  box-shadow:
    inset 0 1px 3px rgba(0, 0, 0, 0.05),
    0 0 8px #40b6ff;
}

What should be changed in that file is the comment before the CSS rules, and the property used for those roles.

Automatically closed - issue fixed for 2 weeks with no activity.