enable "zeobased" for datatypes line and scatter too

Hi,

in my usecase the datatypes line, area, bar and scatter have the same settings. So we need the option `zerobased` for line and scatter to have a unique behaviour.

I have already implemented this change and would like to make a pull request.

My enchanchment will not change the bahaviour of C3. It only gives the option to choose zerobased for line and scatter types.

any objections?

The issue concerns the existing `zerobased` option and the line, area, bar, and scatter datatypes, but names no files or tests. Start by locating the current `zerobased` handling for area and bar, then compare the line and scatter configuration paths. Done means line and scatter accept the option while existing C3 behavior remains unchanged.

Written by the indexing model from the issue text.