Changed the blur thing with a simple label

It was a bit buggy and was not blurring all the widgets, or
not reverting the blur properly. Probably best to just show a
label instead.

Still, the proper solution would probably be to do the processing
in a separate thread.

relational_gui/maingui.ui

@@ -326,6 +326,17 @@
          </item>
         </layout>
        </widget>
+       <widget class="QWidget" name="processing">
+        <layout class="QVBoxLayout" name="verticalLayout_6">
+         <item>
+          <widget class="QLabel" name="label_2">
+           <property name="text">
+            <string>Processing…</string>
+           </property>
+          </widget>
+         </item>
+        </layout>
+       </widget>
       </widget>
      </widget>
     </item>