TODO: Use HTMLApplier or formatInline here

Turns selection into a link
If selection is already a link, it removes the link and wraps it with a <code> element
The <code> element is needed to avoid auto linking

@example
// either ...
wysihtml5.commands.createLink.exec(composer, "createLink", "http://www.google.de");
// ... or ...
wysihtml5.commands.createLink.exec(composer, "createLink", { href: "http://www.google.de", target: "_blank" });
function(composer, command, value) {
      var anchors = this.state(composer, command);
      if (anchors) {
        // Selection contains links
        composer.selection.executeAndRestore(function() {
          _removeFormat(composer, anchors);
        });
      } else {
        // Create links
        value = typeof(value) === "object" ? value : { href: value };
        _format(composer, value);
      }
    }