Update Blocklayer to deal with Block1 option

On the last block answer, the Client still sent another empty message, it didn't take into account the fact that the previous block was sent with m=0. This commit fixed that for me.

coapthon/layers/blocklayer.py

@@ -141,10 +141,10 @@ class BlockLayer(object):
             item.num += 1
             item.byte += item.size
             if len(item.payload) <= item.byte:
-                m = 0
+                item.m = 0
             else:
-                m = 1
-            request.block1 = (item.num, m, item.size)
+                item.m = 1
+            request.block1 = (item.num, item.m, item.size)
         elif transaction.response.block2 is not None:
 
             num, m, size = transaction.response.block2