Ice labs and get_temperature() function

[Shoes01]

Half the labs will now be "ice labs", which are labs that get increasingly cold as you descend the depths.

To accomplish this, the get_temperature function was added. It checks to see if the player is in an ice lab, and if so it returns a different temperature value. The weather's temperature value is not changed, so weather will not be affected. It would be trivial to add temperature variation for more buildings.

I have tested this a little bit. I've walked around in both kinds of labs to make sure there is no sillyness. edit: frostbite is working as intended, silly me!

[Shoes01]

The first commit implies ice labs are different color. They are not anymore.

[CataJenkins]

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[KA101]

Since labs can go fairly deep (I think I've seen one get to Z-4, and it had a Stairs Down), they ought to cap at some temperature MUCH higher than -273C. At minimum, any ice lab ought to be a Portal finale that's sucking the heat out or something.

As it stands, I'd hope that there's some way to thaw the labs/disable the "feature". Labs becoming increasingly inaccessible because ...Shoes isn't much fun.

[Shoes01]

I thought of you when I added this!! Another added difficulty with no reward or reason :D

At the moment, the labs are literally identical. I am not sure how possible it is to "fix" the lab's heat problem; I am not sure the code is built that way. I did not investigate. But yeah, I would like to add a bit of flavor to the lab making it more unique. Frozen zombies, unique loot.

Also, I am aware that it's probably impossible to reach the lowest level (which I think is ten) and still keep warm. I think it's a little haunting to have a lab that goes deeper than you can possible go.

Also, you will like this : the new function I added allows me to make a distinction between outdoor and indoor weather. If I wanted to, I could make all indoor weather a couple of degrees warmer or something like that. I haven't put much thought into it, but aside from the math it's trivial to add now.

[i2amroy]

It would be nice to have it slightly warmer indoors then outside.

I do think that this should probably be a little less then half of the labs though, maybe 1/4 or 1/3.