MEDIUM: Prevented NPE when creating screenshots
LOW: Prevented NPE
IMPORTANT: Splitted screenshot generation into 3 phases so that views
that need SwingUtilities.invokeLater() to be run can rely properly on
that mechanism.
LOW: center() of PRogresswindow should always be called after pack().
IMPORTANT: Fixed issues with start on new page
RESOLVED - issue OPENFLEXO-257: different order in TOC perspective 
https://bugs.openflexo.com/browse/OPENFLEXO-257