Fix performance problems for Combine/Separate

The change in 235be9f to use
arrays instead of gb_trees for the edge table made Combine and
Separate much slower if there were many objects in the scene
because array:from_orddict/1 does not create sparse arrays if
there are holes in the index numbering.

This problem is best fixed in array.erl to make sure that
array:from_orddict/1 creates sparse arrays. Include the fixed
version of array.erl in Wings until R13B03 has been released.

NOTE: Combine and Separate became much slower in 1.1 if there
were many objects in the scene. This has been corrected.
(Thanks to ycarry.) [dgud/bjorng]

src/Makefile

@@ -38,6 +38,7 @@ endif
 # rule to ensure that it gets compiled before all other modules.
 
 MODULES= \
+	array \
 	user_default \
 	wings \
 	wings_align \