Re-implement more efficient GetBust

Was lost in a merge at a2049be03ac5adf025f645815c70d8d9b1316425
Merge branch 'master' into fix-bust-efficient
Reduce duplication in GetBust/GetBody
Put 1.8 Skin check in function
Merge remote-tracking branch 'luke/fix-bust-efficient' into faster-getbust

Conflicts:
	process.go