Bitcoin-Qt: give testnet a unique IPC message queue name

- this prevents an interference with the IPC message queue (which is used
  for URI processing) when running a testnet and mainnet instance in
  parallel
- to check for testnet, I had to raise the ParseParameters() call in
  main() to the topmost position

src/qt/qtipcserver.h

@@ -1,8 +1,14 @@
 #ifndef QTIPCSERVER_H
 #define QTIPCSERVER_H
 
-// Define Bitcoin-Qt message queue name
-#define BITCOINURI_QUEUE_NAME "BitcoinURI"
+#include <string>
+
+// Define Bitcoin-Qt message queue name for mainnet
+#define BITCOINURI_QUEUE_NAME_MAINNET "BitcoinURI"
+// Define Bitcoin-Qt message queue name for testnet
+#define BITCOINURI_QUEUE_NAME_TESTNET "BitcoinURI-testnet"
+
+extern std::string strBitcoinURIQueueName;
 
 void ipcScanRelay(int argc, char *argv[]);
 void ipcInit(int argc, char *argv[]);