Weld More Of The Things

Adds the oxyacetylene torch to the following recipes, costing 1/10th of the charges the welder would require (based on the steel_lump recipe):
cargo rack
muffler
basket
xlframe
sheet_metal
metal_tank
metal_tank_small
metal_tank_little
jackhammer
chainsaw_off
char_kiln
char_smoker
char_forge
forge

I'm not sure whether Rivet meant to exclude it for these, and if so, what her reasoning was, so I'd appreciate her weighing in on this.

I was originally inclined to decline it for fine-detail work such as the jackhammer, chainsaw, etc but its preexisting use in gunsmithing seemed to invalidate that reasoning.  :-/