This should provide a better out-of-the-box experience when using PDF.js in a Node.js environment, since it's missing native support for both `@font-face` and `Image`.
Please note that this change *only* affects the default values, hence it's still possible for an API consumer to override those values when calling `getDocument`.
Also, prevents "ReferenceError: document is not defined" errors, when running the unit-tests in Node.js/Travis.
We need to pass `disableFontFace` and `nativeImageDecoderSupport`
because Node.js has no native support for `@font-face` and `Image`.
Doing so makes it possible to render e.g., the Tracemonkey paper, which
failed before. I made this PDF file the default because it's also the
default in other examples/demos and because it showcases the
possibilities better than the very simple hello world PDF file.
Building the library with `gulp dist-install` is easier and is already
recommended in the other examples.
