fix null pointer error
Now skipping StreamObjects with undefined bounds in
groupStreamObjectsIntoTiles().
fixed submenu toggle functionality
Moved 'clear history' function to submenu.
Added temporary branch feature.
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Merge branch 'patrickR'
pen tool now ignores mouse events when one of alt/shift/ctrl is pressed.
pen tool polygon mode now requires point click event.
Merge branch 'patrickR'