[add massocs method
John Meacham <john@repetae.net>**20060420044029] hunk ./Util/SetLike.hs 133
+    massocs :: m -> [(k,v)]
hunk ./Util/SetLike.hs 137
+    mkeys = map fst . massocs
+    melems = map snd . massocs
hunk ./Util/SetLike.hs 148
+    massocs = IM.toList
hunk ./Util/SetLike.hs 158
+    massocs = M.toList