function addListToWorkingSet(fileList) {
        var uniqueFileList = [];

        // Process only files not already in working set
        fileList.forEach(function (file) {
            // If doc is already in working set, don't add it again
            if (findInWorkingSet(file.fullPath) === -1) {
                uniqueFileList.push(file);

                // Add
                _workingSet.push(file);

                // Add to MRU order: either first or last, depending on whether it's already the current doc or not
                if (_currentDocument && _currentDocument.file.fullPath === file.fullPath) {
                    _workingSetMRUOrder.unshift(file);
                } else {
                    _workingSetMRUOrder.push(file);
                }
            }
        });

        // Dispatch event
        $(exports).triggerHandler("workingSetAddList", [uniqueFileList]);
    }
Adds the given file list to the end of the working set list.
Does not change which document is currently open in the editor.
More efficient than calling addToWorkingSet() (in a loop) for
a list of files because there's only 1 redraw at the end
@param {!FileEntryArray} fileList