Don't implement zoom/move speedups if distance estimator AND jitter

Comments, whitespace

Consistency is helpful for finding code …

Switch back to fixed-point, when appropriate

Simplify Settings code

We no longer compare old with new settings.
Instead we compare current values with those from Settings
(new if set, current otherwise). Thus incremental changes are easy
(update NewSettings without moving it to Settings), as is reverting them
(remove newSettings and call ApplySettings).

ChgXXX macros now answer the question
"do the (new) settings change parameter XXX".

Handle re-rendering (or not)

Needs some cleanup.

Add a way to check whether applying new settings is OK in the current…

… situation.

Use a saved config object for the color dialog

doesn't actually exist

Merge remote-tracking branch 'intern/demutex'

Export settings as string