Icon created and contributed by colombo-bt.i2p

- Add Greek language
- Update Dutch translation
- Adjust flag rows

This does mean that the iframe don't-refresh state (= refresh rate of 0 seconds)
doesn't hold if the page is changed (in fact, the refresh rate becomes the
minimum) - so maybe better to have a different config var for that?

Also adding form handler class that I forgot to commit earlier.

/i2ptunnelmanager redirects to /i2ptunnel/ if the browser doesn't support IFrames.

Now, Ajax will be used first, and will fall back to IFrame if JS is disabled,
and a separate page if on a text or mobile browser.
Also, /home and /console (and everywhere) now all have the same summary bar
content, which currently defaults to the original full listing.

The initial attempt using mapping of strings to methods is shorter and neater,
but also doesn't work so is commented out.