Fixed editable shape settings.

Editable shape settings should now be updated, stored, and recalled
intuitively.

All quadruple spaces in ArrowedEditEngine were replaced with tabs.
Several methods in the class were removed, and several overrides (to the
new BaseEditEngine methods) were added.

Also, "Open/Closed Curve Series" was changed to "Open/Closed Curve
Shape" and "Rounded Line Series" was changed to "Rounded Line Shape"
(for easier understanding for users).