Added recipe search by skill function [WIP] [CR]

I need help with this one. I've spent the last hour trying to get this not to crash, and C::B does not provide an error, so who knows what's going on.

The intent is to be able to search "s:cooking" and get recipes that use the cooking skill. It checks both "skill used" and "require skills". 

The require skills (line 1022) works great, but as soon as I try to access "skill_used->name()" (line 1021), the game crashes. No error, debug mode or not. Breakpoints don't work. I've trying smart things and I've tried dumb things. Now I appeal to whoever will listen!