Unfiy makeDiv/Span

The reason I have two functions is that classNames and parent are optional and turning the parameter into an object makes the function calls a lot longer which is just annoying, especially since they are intended to be used a lot.

I am not sure whether tag or content should be the first parameter. Usually content is first in similar functions, but I find it easier to read if you first see which element it is and then the content. (You are going to interpret the content quite differently if it's in a div rather than a span)