Refactor main drawing function

We add a redraw function which redraws. This will be needed for zooming, maybe
later I can do some prefilter, if needed, to remove extra elements. In addition,
we refactor what is done to draw elements. For example, we do not need to add
the data like sequence and nts to nucleotides, interactions and such. We should do
filtering not using css selectors, but instead using data attributes. This
change forces that. We change the standardBuild function to make it simpiler to
build things because of these changes.
Fixes #3

We now have a basic zoom working. This allows us to focus in on one region to
see it clearly. I still should add more features like labels that only appear
on high zoom, or letters in circular that appear at high zoom and the like. But
this is a good enough start.