ruby: rename building_isitemfree to item_isfree, add trader flag check

plugins/ruby/building.rb

@@ -352,23 +352,13 @@ module DFHack
             job
         end
 
-        # check item flags to see if it is suitable for use as a building material
-        def building_isitemfree(i)
-            !i.flags.in_job and
-            !i.flags.in_inventory and
-            !i.flags.removed and
-            !i.flags.in_building and
-            !i.flags.owned and
-            !i.flags.forbid
-        end
-        
         # exemple usage
         def buildbed(pos=cursor)
             raise 'where to ?' if pos.x < 0
 
             item = world.items.all.find { |i|
                 i.kind_of?(ItemBedst) and
-                building_isitemfree(i)
+                item_isfree(i)
             }
             raise 'no free bed, build more !' if not item
 

plugins/ruby/item.rb

@@ -47,5 +47,17 @@ module DFHack
                 raise "what what?"
             end
         end
+
+        # check item flags to see if it is suitable for use as a job input material
+        def item_isfree(i)
+            !i.flags.trader and
+            !i.flags.in_job and
+            !i.flags.in_inventory and
+            !i.flags.removed and
+            !i.flags.in_building and
+            !i.flags.owned and
+            !i.flags.forbid
+        end
+        
     end
 end