Enhance addon-tostring to use a commons-lang builder and remove addon-displaystring

Having two add-ons to generate toString-style methods is not ideal and so this improvement will modify the output of @RooToString to be more compatible for display in UI views as well as removing the need to have the addon-displaystring. The JSF and MVC add-ons can simply use the toString() method to display entity data in tables as well as for JSF Converters.

The toString add-on will now make use of the commons-lang ReflectionToStringBuilder to generate the toString() method which can handle nulls, collections etc without the need for the add-on itself to handle such conditions. Of course for each entity, the toString() method can be pushed in and customized.