#2 Make usage of no images possible

[Morten Wang]

Instead of having lots of images showing the tree,
make it possible to switch to "no-images", meaning no
+/- signs, transparent GIFs to make the left margin,
etc...

[Nobody/Anonymous]

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Hmm..
I think the +/- signs should remain, but an option to not
having any icons images would be nice. Then it should be
faster for very large & BIG tree..