Large changes to Socket/UPS handling

- New Nut_Exception constructor to allow specifying NUTResponse instead of _Exception_Value
- Shifted some responsibility of error handling out of Socket class and into UPS class. These are some major changes and need testing.
- Merged Create_Socket code into Connect code
- Renamed and then commented-out IsKnownUPS function. Feels like this should be a part of the UPS class, but regardless, we'll know if there's an invalid UPS the moment a command is run for one.
- Simplified & renamed Query_Desc function
- Added a few events to the UPS class for informing any listeners of issues
- UPS no longer handles socket errors, and instead passively notifies listeners about one
- GetUPSVar supports DATA-STALE errors and will retry 3 times to get the data, and then take the default value and raise an event about the error.
- If error is encountered when opening the ListVarGUI, display a message box and close the form.
- Removed the Unknown_UPS event and modified the GUI to handle future errors.

Author: gbakeman

WinNUT_V2/WinNUT-Client_Common/Common_Classes.vb

@@ -36,6 +36,7 @@ Public Class Nut_Exception
     Inherits System.ApplicationException
 
     Public Property ExceptionValue As Nut_Exception_Value
+    Public Property ProtocolError As NUTResponse
 
     Public Sub New(ByVal Nut_Error_Lvl As Nut_Exception_Value)
         MyBase.New(StringEnum.GetStringValue(Nut_Error_Lvl))
@@ -45,6 +46,16 @@ Public Class Nut_Exception
         MyBase.New(StringEnum.GetStringValue(Nut_Error_Lvl) & Message, innerEx)
         ExceptionValue = Nut_Error_Lvl
     End Sub
+
+    ''' <summary>
+    ''' Raise a Nut_Exception that resulted from an error as part of the NUT protocol.
+    ''' </summary>
+    ''' <param name="protocolError"></param>
+    ''' <param name="message"></param>
+    Public Sub New(protocolError As NUTResponse, message As String)
+        MyBase.New(message)
+        Me.ProtocolError = protocolError
+    End Sub
 End Class
 
 Public Class Nut_Parameter