Fixed major bug EXT-2620 (IM Chiclet Panel goes crazy when new IM chiclets are...

Fixed major bug EXT-2620 (IM Chiclet Panel goes crazy when new IM chiclets are added (chiclet scrolling appears with no need))
 - refactored algotithm of caclulating position of the first chiclet in the list when adding new one.
 - added comments for LLChicketPanel::addChiclet() & LLChicketPanel::arrange() methods

--HG--
branch : product-engine