Fix selection to use unicode keys and set str in gtk for issue422

tryton/common/common.py

@@ -156,7 +156,7 @@ def selection(title, values, parent, alwaysask=False):
     keys = values.keys()
     keys.sort()
     for val in keys:
-        model.append([val])
+        model.append([str(val)])
 
     sel_tree.set_model(model)
     sel_tree.connect('row-activated',

tryton/plugin.py

@@ -21,8 +21,6 @@ def execute(datas, parent):
     for module in MODULES:
         try:
             for name, func in module.get_plugins(datas['model']):
-                # Use str as key to use in the ListStore of common.selection
-                name = name.encode('utf-8')
                 result[name] = func
         except Exception, exception:
             continue