Increase maximum orphan size to 100,000 bytes.

Although this increases node memory usage in the worst case by perhaps
 30MB, the current behavior causes severe issues with dependent tx relay.

src/test/DoS_tests.cpp

@@ -162,7 +162,7 @@ BOOST_AUTO_TEST_CASE(DoS_mapOrphans)
         tx.vout.resize(1);
         tx.vout[0].nValue = 1*CENT;
         tx.vout[0].scriptPubKey = GetScriptForDestination(key.GetPubKey().GetID());
-        tx.vin.resize(500);
+        tx.vin.resize(2777);
         for (unsigned int j = 0; j < tx.vin.size(); j++)
         {
             tx.vin[j].prevout.n = j;