Unlike the old version, the new version no longer stores string value
for non-string items.  We need to call GetFormattedString() for that.

-Update ModelState to reflect the changes.

Select the errorbar propertyset according to the errorbar direction
instead of only using Y errorbar propertyset in ObjectIdentifier::getObjectPropertySet
function.

- Make StatisticsItemConverter work with X and Y errorbars.
- Fill errorbar type property in ErrorBarResources.
- Set default value of errorbar type property to Y bar.

- Dispatch the commands to the proper functions.

- Added needed strings resources and ids.
- Added code to handle X and Z errorbars.

- Make the function usable for XError and YError bars.
- Rename executeDispatch_InsertYErrorBars to executeDispatch_InsertErrorBars.
- Add a new parameter that control the error bar direction.
- Update arguments in callers.

- Require passing desired error bar to modify in constructor
and not have YErrorBar as default.