allow for filtering addresses and labels by searching for the typed string anywhere, not just at the beginning (#641)

src/qt/transactionfilterproxy.cpp

@@ -35,7 +35,7 @@ bool TransactionFilterProxy::filterAcceptsRow(int sourceRow, const QModelIndex &
         return false;
     if(datetime < dateFrom || datetime > dateTo)
         return false;
-    if(!address.startsWith(addrPrefix) && !label.startsWith(addrPrefix))
+    if (!address.contains(addrPrefix, Qt::CaseInsensitive) && !label.contains(addrPrefix, Qt::CaseInsensitive))
         return false;
     if(amount < minAmount)
         return false;