-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.

SwEditShell::Undo: Because the Undo actions nowadays create new shell
cursors directly (while previously they worked on a SwUndoIter), it is
necessary to remove the shell cursor ring before Pop() because Pop(false)
only restores the current cursor from the stack, not the rest of the ring.
(regression from CWS undoapi, 1ba0c187)