always add height to line wrapper nodes
 (needed for line widgets)
hack edit session
add first version of line_widgets
fix typo
fix cursor movement
allow widgets to have any height
cleanup kitchen-sink demo
do not round mouse position since lines can have fractional screen coordinates now
semicolonify demo files;
Merge pull request #1678 from ajaxorg/line_widgets_pt1

Add support for line widgets
fix static highlight bugs

#1681 #1682
Merge pull request #1683 from ajaxorg/static_highlight

fix static highlight bugs