Merge #7648: BIP9 versionbits softfork for BIP68, BIP112 and BIP113

71527a0 Test of BIP9 fork activation of mtp, csv, sequence_lock (NicolasDorier)
19d73d5 Add RPC test for BIP 68/112/113 soft fork. (Alex Morcos)
12c89c9 Policy: allow transaction version 2 relay policy. (BtcDrak)
02c2435 Soft fork logic for BIP68 (BtcDrak)
478fba6 Soft fork logic for BIP113 (BtcDrak)
65751a3 Add CHECKSEQUENCEVERIFY softfork through BIP9 (Pieter Wuille)

qa/rpc-tests/test_framework/comptool.py

@@ -179,6 +179,10 @@ class TestManager(object):
             # associated NodeConn
             test_node.add_connection(self.connections[-1])
 
+    def clear_all_connections(self):
+        self.connections    = []
+        self.test_nodes     = []
+
     def wait_for_disconnections(self):
         def disconnected():
             return all(node.closed for node in self.test_nodes)