Add SampleApp that shows problems in stroking

gyp/SampleApp.gyp

 # Copyright 2015 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 #
 {
   'targets': [
     {
       'target_name': 'SampleApp',
       'type': 'executable',
@@ skipping 76 matching lines @@
         '../samplecode/SampleLitAtlas.cpp',
         '../samplecode/SampleLua.cpp',
         '../samplecode/SampleManyRects.cpp',
         '../samplecode/SampleMeasure.cpp',
         '../samplecode/SampleMegaStroke.cpp',
         '../samplecode/SamplePatch.cpp',
         '../samplecode/SamplePath.cpp',
         '../samplecode/SamplePathClip.cpp',
         '../samplecode/SamplePathFuzz.cpp',
         '../samplecode/SamplePathEffects.cpp',
+        '../samplecode/SamplePathOverstroke.cpp',
         '../samplecode/SamplePictFile.cpp',
         '../samplecode/SamplePoints.cpp',
         '../samplecode/SamplePolyToPoly.cpp',
         '../samplecode/SampleQuadStroker.cpp',
         '../samplecode/SampleRectanizer.cpp',
         '../samplecode/SampleRegion.cpp',
         '../samplecode/SampleRepeatTile.cpp',
         '../samplecode/SampleShaders.cpp',
         '../samplecode/SampleShaderText.cpp',
         '../samplecode/SampleShip.cpp',
@@ skipping 150 matching lines @@
           ],
         }],
         [ 'not skia_pdf', {
           'dependencies!': [ 'pdf.gyp:pdf' ],
           'dependencies': [ 'pdf.gyp:nopdf' ],
         }],
       ],
     },
   ],
 }