helper - sumarize file info
@param {String} fileId
@param {Object} stat fsStat object
@param {String} filePath
@returns {Object}  file info object
function getFileItem(fileId, stat, filePath){
    return {
        id:fileId,
        fullPath: filePath,
        name: getName(fileId, !stat.isDirectory()),
        ancestors: getPathAncestors(fileId),
        isDir:stat.isDirectory(),
        isFile:!stat.isDirectory(),
        ext:!stat.isDirectory() ? getExt(fileId) : null,
        modifiedDT: stat.mtime, // (stat.ctime.getTime() > stat.mtime.getTime()) ? stat.ctime : stat.mtime,
        createdDT: stat.birthtime,
        size: stat.size
    };
}