o Fix STR#2828 (E): {Vertical|Widget} Gap
o Moved Fabien's reselected methods to Fl_Tree_Prefs,
return method made const, doxygen, removed underbars from methods
(to follow general API)
o Widgets can now appear to the right of labels.
This can be controlled with item_draw_mode(FL_TREE_ITEM_DRAW_LABEL_AND_WIDGET)
o Cleaned up Fl_Tree_Item::draw(), Fl_Tree::draw()
o New methods:
marginbottom() -- [ABI feature] extra space below last tree element when scrolling
widgetmarginleft() -- [ABI feature] space to left of widget
usericonmarginleft() -- space to left of usericon
labelmarginleft() -- space to left of label
item_draw_mode() -- control how items, widget() are drawn
o Updated Fl_Tree docs, tree-elements.png
o test/tree: added sliders to test the above new features,
added "open all" and "close all" buttons
o Probably other stuff..
TODO: Fix "scroll-beyond-bottom" (STR#2796)
TODO: Fix other items in STR#2828
git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@9377 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
o Don't draw FLTK widgets outside tree's viewport.
o Added tree-as-container.cxx example program, demos tree
w/50k tree items each with 6 widgets (300k total)
git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@9356 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
