[New document] was broken

[cben]

[cben]

This was (A) dumb bug I should have seen (B) has no tests (C) seriously broke stuff for ~5 days!

hot-fixed by 7c7d63c.

Not sure the window.newPad = newPad; fix is elegant; now that I have a server side, the right thing probably involves a server side redirect e.g. /new/ -> random, pointing href there (actually no, it must be a button with POST), and unobtrusively attaching .onclick = newPad or dropping it entirely.
[That's also a good time to stop using weak Math.random in browsers without strong random]

But first, tests.

[cben]

re POST: should consider what happens when running from local files.
For some reason googling didn't answer the simple question whether POST to a file:// URL works. Perhaps the question is too dumb.