Differentiate between unused 'import X' and unused 'from X import *'

From: Daniel Drake <d.drake@mmm.com>

Index: pylint-0.12.2/checkers/variables.py
===================================================================
--- pylint-0.12.2.orig/checkers/variables.py
+++ pylint-0.12.2/checkers/variables.py
@@ -61,7 +61,10 @@ MSGS = {
               'Used when a variable is defined but not used.'),
     'W0613': ('Unused argument %r',
               'Used when a function or method argument is not used.'),
-    
+    'W0614': ('Unused import %s from wildcard import',
+              'Used when an imported module or variable is not used from a \
+              \'from X import *\' style import.'),
+
     'W0621': ('Redefining name %r from outer scope (line %s)',
               'Used when a variable\'s name hide a name defined in the outer \
               scope.'),
@@ -134,9 +137,13 @@ builtins. Remember that you should avoid
             return
         for name, stmts in not_consumed.items():
             stmt = stmts[0]
-            if isinstance(stmt, astng.Import) or (
-                isinstance(stmt, astng.From) and stmt.modname != '__future__'):
+            if isinstance(stmt, astng.Import):
                 self.add_message('W0611', args=name, node=stmt)
+            if isinstance(stmt, astng.From) and stmt.modname != '__future__':
+                if stmt.names[0][0] == '*':
+                    self.add_message('W0614', args=name, node=stmt)
+                else:
+                    self.add_message('W0611', args=name, node=stmt)
         del self._to_consume
         del self._vars