React-pdf: Add fonts embedding support

[diegomura]

For ref: https://github.com/devongovett/pdfkit

[jbovenschen]

Currently working on this, and getting text to work again.

My ideas about this are;

<Document>
  <Font familty="Some" src="some-source" weight="bold" />
</Document>

Or doing it this way:

<Document 
  author="jbovenschen" 
  fonts=[{ family: 'Some', sources: [{ src: 'some-source', weight: 'bold' }] }]
/>

What do you like the most?

[diegomura]

I prefer the second approach. What do you think?
Manly because is a styling thing. I'll keep the Component approach for things that will actually be rendered as meaningful piece of document

[jbovenschen]

Yeah, I also prefer the second approach that one would make it easier to build a component library for this renderer. Also it's mainly meta data.

Will work on the second one!

[diegomura]

Closing this because of #44