remove PlotRegistry type

[ElenaPochernina]

#79

[dvoits]

What is the reason to remove plot registry? That allows to add new types of plots dynamically and is more generic solution than hard-coded basic plots as in the pull request.

[dgrechka]

@dvoits , You've created the issue #79: "The ChartViewer's PlotRegistry duplicates the registry of IDD and can be eliminated."

Please decide whether ChartViewer's PlotRegistry is useful or harmful as duplicates functionality.

:-)