Add NODE_BLOOM service bit and bump protocol version

Lets nodes advertise that they offer bloom filter support explicitly.
The protocol version bump allows SPV nodes to assume that NODE_BLOOM is
set if NODE_NETWORK is set for pre-70011 nodes.

Also adds an option to turn bloom filter support off for nodes which
advertise a version number >= 70011. Nodes attempting to use bloom
filters on such protocol versions are banned, and a later upgade
should drop nodes of an older version which attempt to use bloom
filters.

Much code stolen from Peter Todd.

Implements BIP 111

src/main.cpp

@@ -4591,6 +4591,21 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
     }
 
 
+    else if (!(nLocalServices & NODE_BLOOM) &&
+              (strCommand == "filterload" ||
+               strCommand == "filteradd" ||
+               strCommand == "filterclear") &&
+              //TODO: Remove this line after reasonable network upgrade
+              pfrom->nVersion >= NO_BLOOM_VERSION)
+    {
+        if (pfrom->nVersion >= NO_BLOOM_VERSION)
+            Misbehaving(pfrom->GetId(), 100);
+        //TODO: Enable this after reasonable network upgrade
+        //else
+        //    pfrom->fDisconnect = true;
+    }
+
+
     else if (strCommand == "filterload")
     {
         CBloomFilter filter;