[0.6.0] Steel furnace visible in craft menu too soon

[FrozenOne]

Steel and electric furnace is visible in craft menu even before steel is invented.
Electric furnace can be built before it's invented.

Edit: Also steel furnace erroneously lists electric comsumption.
Edit 2: Oh it probably means energy from coal.

[slpwnd]

Thanks for the report. Fixed for 0.6.1.