Front-to-back conversion testing

This contains tests for full front-to-back conversion.

The basic idea here, is to start with a javascript object, convert that to a document, then run that through the full process. The reason why this approach was chosen is that by definition of an HTML file, not only our parsing process, and the writing of HTML files, the files wouldn't be *exactly* the same before and after, because of formatting. Because of this, the only options left were this (the idea being that if a file was not altered, it should maintain the same contents **exactly**), or to do POR Object comparison, which is also error-prone.

At some point, we will want to do that, but for now, this is a good start.
closes #61.