Don't send empty theme in config

- Restrict game config changes in special rooms - /unfix command

Experiment in adding a "boing" graphic for bouncing. It has no text right now (was thinking l10n) and colour is fixed.

Add rubber utility. Graphics are still incomplete. Also flag snow/ice in theme config.

Add missing gstCollision bug #725

fix issue #724: Bee sound never stops (underwater when timer is 0) also: instead of flowers add bubbles while underwater

string/typo fixes

revert r938d1c08d0d1 in favour of putting it in the chat log. I think this addresses main concern about missing text. There've been complaints in past too about conversation in bubbles not being visible in history. If the objection is that r938d1c08d0d1 offers a more æsthetic solution, I think it should augment this, be flagged, and fix the visual issues first.

use a variable that allows negative values instead.

disallow speech bubbles to go offscreen no tint or tail-directio adjustments for indicating it's offscreen yet though