Changed windchill model [CR]

I've decided to change the windchill model based on this forum post : http://smf.cataclysmdda.com/index.php?topic=8002.msg184741#msg184741

There is a bug in my code that I am blind to : windchill always turns "1" ??? I don't understand why. Hoping someone with C++ experience could point it out.

This PR also adds a debug item, the pocket meteorologist, which simply messages the player the absolute temp, pressure and humidity. Once the windchill=1 bug is fixed, I can remove the item if necessary.
If this is going to stick around, I'd far rather it have an iuse method that outputs to the log when active or something.
The sidebar is already complicated enough without adding debug features to it.