Mass items performance improved in monitor mode

When the UI thread detects it's been blocked for a short while, busy inserting new items, it signals the read thread to copy everything into its local list and give back the complete list when the readers wait the next time. Timeouts and queue lengths have been decreased. All items remain visible and user interaction is possible (mostly). The counter indicator shows the total number of log items counted in the read thread and indicates something big coming... On the read waiting event (OnReadWaiting method), the ObservableCollection is replaced again, but keeping the selection/updating the scroll state when possible.
Fixed opening another file; New filter with "contains" operator

* Fixed opening another file after one has been loaded
* New filter starts with contains operator instead of equals
* Logging after FieldLog shutdown doesn't throw an exception anymore but writes the message to Trace.WriteLine (in case somebody looks at it, but at least the program doesn't crash when another thread is still doing its last thing while the application is shut down)
Exception error code is also displayed in hex notation
Added TextBox in the toolbar to search text within filtered items