Don't use checkpoints and accept nonstd txn on -regtest

src/checkpoints.cpp

@@ -67,11 +67,24 @@ namespace Checkpoints
         300
     };
 
+    static MapCheckpoints mapCheckpointsRegtest =
+        boost::assign::map_list_of
+        ( 0, uint256("0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206"))
+        ;
+    static const CCheckpointData dataRegtest = {
+        &mapCheckpointsRegtest,
+        0,
+        0,
+        0
+    };
+
     const CCheckpointData &Checkpoints() {
-        if (TestNet())
+        if (Params().NetworkID() == CChainParams::TESTNET)
             return dataTestnet;
-        else
+        else if (Params().NetworkID() == CChainParams::MAIN)
             return data;
+        else
+            return dataRegtest;
     }
 
     bool CheckBlock(int nHeight, const uint256& hash)