Added ability to change time format string for when you're in System

Clock mode. Fixed code so that editing settings in the settings dialog
will now immediately take effect in the program.

canframemodel.cpp

@@ -69,6 +69,7 @@ CANFrameModel::CANFrameModel(QObject *parent)
     timeOffset = 0;
     needFilterRefresh = false;
     lastUpdateNumFrames = 0;
+    timeFormat =  "MMM-dd HH:mm:ss.zzz";
 }
 
 void CANFrameModel::setHexMode(bool mode)
@@ -114,6 +115,13 @@ void CANFrameModel::setInterpetMode(bool mode)
     }
 }
 
+void CANFrameModel::setTimeFormat(QString format)
+{
+    timeFormat = format;
+    beginResetModel(); //reset model to show new time format
+    endResetModel();
+}
+
 void CANFrameModel::normalizeTiming()
 {
     mutex.lock();
@@ -252,7 +260,7 @@ QVariant CANFrameModel::data(const QModelIndex &index, int role) const
                 if (!timeSeconds) return QString::number(thisFrame.timestamp);
                 else return QString::number((double)thisFrame.timestamp / 1000000.0, 'f', 6);
             }
-            else return QDateTime::fromMSecsSinceEpoch(thisFrame.timestamp / 1000).toString("MMM-dd HH:mm:ss.zzz");
+            else return QDateTime::fromMSecsSinceEpoch(thisFrame.timestamp / 1000).toString(timeFormat);
             break;
         case 1: //id
             return Utility::formatNumber(thisFrame.ID);