First draft of template engine chapter

I've added myself to the table of contributors, but I have a few questions about the information we're choosing to present.
I might merge this example with your statement above -- the one about how we could just assign static HTML blocks to constants and then emit them and our dynamic blocks with `print` statements to produce a document. 

But, since we want our designers to have a familiar interface (the document), what if we turn this relationship on its head and have the document contain the `print`s? This could lead into the idea of a "text template", which could then be explained here.