ADDRESSES #77: Integrate Twig.php tests into Twig.js

I hope you like the way I use the Twig.php tests.

I decided to checkout Twig.php via git in my test.original.js-file to avoid adding the tests into the repository and to avoid using a submodule.

It's not all tests I can run, those that use special classes in PHP can't be used.

test.original.js depends on tokenizer so I've added that as a devDependency.
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Morten