Add column_only kwarg for Grid.set_label() method

pass True to affect only the column label and not the filter

tailbone/grids/core.py

@@ -385,9 +385,9 @@ class Grid(object):
     def remove_filter(self, key):
         self.filters.pop(key, None)
 
-    def set_label(self, key, label):
+    def set_label(self, key, label, column_only=False):
         self.labels[key] = label
-        if key in self.filters:
+        if not column_only and key in self.filters:
             self.filters[key].label = label
 
     def get_label(self, key):