Half-documented, and refactored LookupTablePanel so it is always

usable (previously was only usable when a compatible overlay was
selected). Next commit will have finished documentation.

fsl/data/strings.py

@@ -107,10 +107,6 @@ messages = TypeDict({
 
     'HistogramPanel.calcHist'           : 'Calculating histogram for {} ...',
 
-
-    'LookupTablePanel.notLutOverlay' : 'Choose an overlay which '
-                                       'uses a lookup table',
-
     'LookupTablePanel.labelExists' : 'The {} LUT already contains a '
                                      'label with value {}',
 

fsl/fsleyes/colourmaps.py

@@ -914,6 +914,16 @@ class LookupTable(props.HasProperties):
 
         if lutFile is not None:
             self._load(lutFile)
+
+
+    def __str__(self):
+        """Returns the name of this ``LookupTable``. """
+        return self.name
+
+    
+    def __repr__(self):
+        """Returns the name of this ``LookupTable``. """
+        return self.name 
         
 
     def __len__(self):