POR tag added & refactoring repo-to-html for easier unit testing

closes #40 & #38 
This has the code to add POR tags around text elements to keep track of what their IDs are. This is subject to change based on what is found with the XML-text-tail style, but for now, might as well get started implementing our way.

Ian assigned since this is his code and he is working on this actively
While I think that just making the last file in the file array to be the metadata file is abhorrent and should be burned with fire, I think that doing something like: ```fs.readdirSync(currentDir)``` is actually pretty alright, since we want to at least make sure there *is* a metadata file there. If not maybe error instead.