Make output appear in the Visual Studio Error List

.travis.yml

@@ -20,4 +20,5 @@ install:
 script:
   - python cpplint_unittest.py
   - pyflakes cpplint.py
-  - pyflakes cpplint_unittest.py
+  - pyflakes cpplint_unittest.py
+  - python cpplint.py --help

cpplint.py

@@ -1139,7 +1139,7 @@ def Error(filename, linenum, category, confidence, message):
   if _ShouldPrintError(category, confidence, linenum):
     _cpplint_state.IncrementErrorCount(category)
     if _cpplint_state.output_format == 'vs7':
-      sys.stderr.write('%s(%s):  %s  [%s] [%d]\n' % (
+      sys.stderr.write('%s(%s): warning: %s  [%s] [%d]\n' % (
           filename, linenum, message, category, confidence))
     elif _cpplint_state.output_format == 'eclipse':
       sys.stderr.write('%s:%s: warning: %s  [%s] [%d]\n' % (
@@ -6253,7 +6253,7 @@ def PrintUsage(message):
   if message:
     sys.exit('\nFATAL ERROR: ' + message)
   else:
-    sys.exit(1)
+    sys.exit(0)
 
 
 def PrintCategories():