Upgrading flexpaper viewer. Last version fixes some minor bugs.
Fixing also of a bad behavior about the document preview plugin. Indeed after switching between several pictures, the preview plugin behaves like a bad slideshow...
Also, the ESC key does not close the popup of the document preview (when no switching between picture preview has been performed).
Merge branch 'ych-flexpaper-upgrade' of https://github.com/SilverYoCha/Silverpeas-Core into master