Force TechRacer maps when image map is selected. Fixes
Google Code issue #882
If you start a TechRacer map with an image map selected, the resulting map will likely to be completely unplayable.
So this commit disables this.
-- Library for localizing strings in lua scripts
local lang = HedgewarsScriptLoad("Locale/" .. tostring(L) .. ".lua")
function loc(text)
if locale ~= nil and locale[text] ~= nil then return locale[text]
else return text
end
end