Clean up TODO

TODO

@@ -19,17 +19,10 @@ RC = Release Critical (for next release)
 RC  - Review XXX in the code (CODE)
 RC  - Review TODO in the code (CODE)
 RC  - Review output of pylint (CODE)
-    - Keep-alive (HIGH AVAILABILITY) (implemented, to be reviewed and tested)
-      Consider the need to implement a keep-alive system (packets sent
-      automatically when there is no activity on the connection for a period
-      of time).
     - When all cells are OUT_OF_DATE in backup mode, the one with most data
       could become UP_TO_DATE with appropriate backup_tid, so that the cluster
-      stays operational (FEATURE).
+      stays operational. (FEATURE)
     - Finish renaming UUID into NID everywhere (CODE)
-    - Consider using multicast for cluster-wide notifications. (BANDWITH)
-      Currently, multi-receivers notifications are sent in unicast to each
-      receiver. Multicast should be used.
     - Remove sleeps (LATENCY, CPU WASTE)
       Code still contains many delays (explicit sleeps or polling timeouts).
       They must be removed to be either infinite (sleep until some condition
@@ -72,7 +65,7 @@ RC  - Review output of pylint (CODE)
       should be made a singleton (saves the CPU time needed to instanciates all
       the copies - often when a connection is established, saves the memory
       used by each copy).
-    - Review node notfications. Eg. A storage don't have to be notified of new
+    - Review node notifications. Eg. A storage don't have to be notified of new
       clients but only when one is lost.
     - Review transactional isolation of various methods
       Some methods might not implement proper transaction isolation when they
@@ -187,4 +180,6 @@ RC  - Review output of pylint (CODE)
     - Investigate delta compression for stored data
       Idea would be to have a few most recent revisions being stored fully, and
       older revision delta-compressed, in order to save space.
-
+    - Consider using multicast for cluster-wide notifications. (BANDWITH)
+      Currently, multi-receivers notifications are sent in unicast to each
+      receiver. Multicast should be used.