Added a button to go back from progress window

It is possible to go back from the network window
pressing the esc key, but this is not possible
when the device has only a touchscreen / mouse.

Add a "Cancel" button to go back to the main window.

Signed-off-by: Stefano Babic <[email protected]>

SWUpdateGUI.lua

@@ -295,6 +295,15 @@ local progwin = ui.Window:new
               Id = "message-box",
             }
           }
+        },
+        ui.Button:new
+        {
+          Id = "progress-cancel-button",
+          Text = L.BACK,
+          Disabled = true,
+          onClick = function(self)
+            app:switchwindow("network-window", "MainWindow")
+          end
         }
 			}
 		}
@@ -489,6 +498,8 @@ app = ui.Application:new
   msgUser = function(self,msg)
     local prog = msg[-1]
     self:switchtoprog(self)
+    g = self:getById("progress-cancel-button")
+    g:setValue("Disabled", true)
     t = {}
     for field in string.gmatch(prog, "%S+" ) do
       k,v = string.match(field, "(%a+)=\'(.*)\'")
@@ -537,9 +548,13 @@ app = ui.Application:new
     elseif status == STATUS_FAILURE then
       g:setValue("Text", L.FAILURE)
       g:setValue("Style", "color: #ff0000;")
+      g = self:getById("progress-cancel-button")
+      g:setValue("Disabled", false)
     elseif status == STATUS_SUCCESS then
       g:setValue("Text", L.SUCCESS)
       g:setValue("Style", "color: #00ff00;")
+      g = self:getById("progress-cancel-button")
+      g:setValue("Disabled", false)
     elseif status == STATUS_START then
       g:setValue("Text", L.STARTING_UPDATE)
     else