Add some barely functional Parser and Document object stubs, initial gem release to claim the namespace.
Create some stubs for Paragraph and ContentTree objects, enough for us to start thinking about what the emitter API might look like. But not really enough to do anything else.
Added some basic emitters for PDF and HTML paragraphs. Note these are proofs of concept ONLY, not meant for practical use. See examples/simple_emitters.rb to see how they're used.