Bug 547636: Improve exporter view cleaning

Execute view validation and removal of invalid view model elements up to
five times during the JSON Forms export.

ViewModelElements determined to be invalid by the ViewValidator are
removed. However this might again lead to invalid view model elements
(usually the parent). Therefore the view model element validation and
removal is now executed multiple times. To avoid an endless loop this is
restricted to five iterations.

This commit also adds some JavaDoc to the ViewModelHelper.

Change-Id: Ia2631c2bc952bc49aba1f0bb98abca482c5ccd48
Signed-off-by: Stefan Dirix <sdirix@eclipsesource.com>
2 files changed