Move showname tickbox into settings menu, remove the old checkbox

[Crystalwarrior]

Is your feature request related to a problem? Please describe.
Clicking on the shownames checkbox currently causes a lock-up (#68) and the worst part is it's far too easy to do so accidentally, especially on themes with the checkbox close to stuff like input box, "pre", etc.

Describe the solution you'd like
Move the "Shownames" checkbox into the Settings menu, call it "Display Shownames", and only make changes to the IC log after the "Save" button is pressed, meaning you only get 1 lock-up at a specific point.

Describe alternatives you've considered
Keeping both and relying on theme makers doesn't solve the issue of the checkbox being mostly useless during normal gameplay and rarely used for anything, it being a source of lag doesn't help

[oldmud0]

yeah
but i don't want this for 2.10 because it will jack themes up at the last minute. some of them rely on the presence of the button to establish a sense of symmetry