UIMenu: Start scrolling in the middle of the list and keep the selection centered as long as the list isnt at the top or bottom.
Interface option for centered menu scrolling.

So far supported by uimenu.
Change update_pot.sh failure message slightly.
Add data/raw/vehicles.json to lang/extract_json_strings.py.
Seems like a good time to update the .pot file.
fixed bug where null bytes was written to save

and template files
Improved Options loading. Wrong manually configures options wont mess up the following options anymore.
Tabnames are now c_ltgreen to be more visible.
Removed a useless map mPage.
Fix wide wheels not being present on vehicles.
Add gettext to vehicle names.
fixed load-game-with-planted-seed crash
Using a wielded handheld game system now uses up charges. Fixes #2827.
Merge dem bugfixes.
Merge scrolling changes.

Conflicts:
	options.cpp
	ui.cpp
Default to center-scroll.
Don't cache center scroll setting so you can toggle it in-game.
Merge remote branch 'origin/master' into scrolling_option_and_indicator
uimenu: scrollbar has better position calculation, consistent size >= 2.
Formatting tweak