The purpose of this abstract plugin implementation is to provide default
implementations of methods that may be overridden by subclasses.
This is more stable in comparison to an interface, since adding new
methods won't break already existing subclasses.
All subclasses must implement a public non-argument constructor!
public java.lang.String getToolTipText(java.util.Locale locale,
Returns the text that should be shown as tooltip for this plug-in.
Subclasses should override this method to provide a localized text for
a short description of their plug-in functionality.
The default implementation returns null.