renderTitle flag not being respected

Rendertitle flag was only respected if called after calling title method, otherwise it was always [true]. Additionally, in line charts, rendertitle was never checked. The flag now defaults to [true] and is respected by all charts regardless of setting a title.
this refactor is actually not equivalent.  `dots.enter().attr("cx"...` will only apply `cx` to the entering dots.

`dots.attr("cx"...` here applies to both the entering and updating dots (because the enter set gets folded into the update set) once `.enter()` is called.