Snuffleupagus Attempt to provide better default values for the `disableFontFace`/`n…
…ativeImageDecoderSupport` API options in Node.js

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.
Latest commit 0ecc22c Jun 1, 2018