Add time information to output

[tobert]

Add -mtime -atime -ctime to include them in the output. With relatime, it's probably useful enough to see how long the file has been untouched. For apps that write into files, mtime is always useful. ctime is included because while I can't think of a use for it right now, it's on the way and completes the trio.

Also add timestamps to all output. Pick a format for JSON that's easy to load in Javascript (probably unix epoch).