better prevention of inventory relaying during initial download,

message checksum between nodes with 0.2.9 or higher,
optimization level up from -O0 to -O2,
rpc functions: setlabel, getlabel, getaddressesbylabel, getreceivedbyaddress, getreceivedbylabel, listreceivedbyaddress, listreceivedbylabel
 -- version 0.2.9

serialize.h

@@ -19,7 +19,7 @@ class CScript;
 class CDataStream;
 class CAutoFile;
 
-static const int VERSION = 208;
+static const int VERSION = 209;
 static const char* pszSubVer = ".0";
 
 
@@ -809,6 +809,18 @@ public:
             vch.insert(it, first, last);
     }
 
+    void insert(iterator it, vector<char>::const_iterator first, vector<char>::const_iterator last)
+    {
+        if (it == vch.begin() + nReadPos && last - first <= nReadPos)
+        {
+            // special case for inserting at the front when there's room
+            nReadPos -= (last - first);
+            memcpy(&vch[nReadPos], &first[0], last - first);
+        }
+        else
+            vch.insert(it, first, last);
+    }
+
 #if !defined(_MSC_VER) || _MSC_VER >= 1300
     void insert(iterator it, const char* first, const char* last)
     {