several small Qt-related fixes

- make BitcoinGUI::showPaymentACK() use a reference for msg and use our
  own GUIUtil::HtmlEscape() function
- ensure QTimer usage in clientmodel is the same as in walletmodel
- remove an unneeded debug message in walletframe
- flag some parameters as unused in DebugMessageHandler()
- small code formatting changes

src/qt/walletmodeltransaction.cpp

@@ -32,7 +32,7 @@ qint64 WalletModelTransaction::getTransactionFee()
 
 void WalletModelTransaction::setTransactionFee(qint64 newFee)
 {
-    fee=newFee;
+    fee = newFee;
 }
 
 qint64 WalletModelTransaction::getTotalTransactionAmount()
@@ -40,7 +40,7 @@ qint64 WalletModelTransaction::getTotalTransactionAmount()
     qint64 totalTransactionAmount = 0;
     foreach(const SendCoinsRecipient &rcp, recipients)
     {
-        totalTransactionAmount+=rcp.amount;
+        totalTransactionAmount += rcp.amount;
     }
     return totalTransactionAmount;
 }