Adding normalized DOM attribute rendering

This is a first pass at normalization. There is a lot of work going
on in the PropertyPresenter. I believe this dom behavior should be
extracted to a class so as to be a bit more atomic in nature.

Relates to #20
Extracting the property_presenter_dom_helper

These methods were getting rather complicated. I wanted to extract
them for future adjustments.

There are several complications occuring related to dom information.
These ideas need to be cleaned up.

Closes #20
Merge pull request #29 from ndlib/working-on-normalizing-attribute-rendering

Adding normalized DOM attribute rendering