Update dependencies / Fix missing semicolon

* I updated [gulp-util](https://github.com/gulpjs/gulp-util), [through2](https://github.com/rvagg/through2), [bufferstreams](https://github.com/nfroidure/BufferStreams), [mocha](https://github.com/visionmedia/mocha). [proxyquire](https://github.com/thlorenz/proxyquire) and [gulp](https://github.com/gulpjs/gulp).
* I added two missing semicolons.