Leverage emerging regular-table extension system

@jhawk has put together a few of what can be described as "extensions". Since I reimplement many of them here, we should leverage the fact that they're now exported

Row Stripes - https://github.com/jpmorganchase/regular-table/blob/master/examples/row_stripes.md
Row, Column, and Area Mouse selection - https://github.com/jpmorganchase/regular-table/blob/master/examples/row_column_area_selection.md
Row Mouse Selection - https://github.com/jpmorganchase/regular-table/blob/master/examples/row_mouse_selection.md
Column Mouse Selection - https://github.com/jpmorganchase/regular-table/blob/master/examples/column_mouse_selection.md
Area Selection - https://github.com/jpmorganchase/regular-table/blob/master/examples/area_mouse_selection.md

Start by reviewing the exported examples named in the issue: row_stripes.md, row_column_area_selection.md, row_mouse_selection.md, column_mouse_selection.md, and area_mouse_selection.md. Compare those behaviors with the current reimplementations in ipyregulartable and determine how they should use the regular-table extension system. Done means the listed striping and mouse-selection behaviors are leveraged through the exported extensions without duplicated implementations.

Written by the indexing model from the issue text.