Add vulcanize to tools.

tools/vulcanize/node_modules/vulcanize/node_modules/cheerio/node_modules/htmlparser2/node_modules/readable-stream/lib/_stream_passthrough.js

Index: tools/vulcanize/node_modules/vulcanize/node_modules/cheerio/node_modules/htmlparser2/node_modules/readable-stream/lib/_stream_passthrough.js
diff --git a/tools/vulcanize/node_modules/vulcanize/node_modules/cheerio/node_modules/htmlparser2/node_modules/readable-stream/lib/_stream_passthrough.js b/tools/vulcanize/node_modules/vulcanize/node_modules/cheerio/node_modules/htmlparser2/node_modules/readable-stream/lib/_stream_passthrough.js
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index 0000000000000000000000000000000000000000..330c247d401a5c5c2d1eb214502ca2dfd7b8a633
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+++ b/tools/vulcanize/node_modules/vulcanize/node_modules/cheerio/node_modules/htmlparser2/node_modules/readable-stream/lib/_stream_passthrough.js
@@ -0,0 +1,41 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// a passthrough stream.
+// basically just the most minimal sort of Transform stream.
+// Every written chunk gets output as-is.
+
+module.exports = PassThrough;
+
+var Transform = require('./_stream_transform');
+var util = require('util');
+util.inherits(PassThrough, Transform);
+
+function PassThrough(options) {
+  if (!(this instanceof PassThrough))
+    return new PassThrough(options);
+
+  Transform.call(this, options);
+}
+
+PassThrough.prototype._transform = function(chunk, encoding, cb) {
+  cb(null, chunk);
+};