update TODO
backlight: warn if kernel exposes backlight device with bogus max_brightness

We shouldn't silently tape over broken kernel drivers.
bus: simplification
label: there is no label_retest_selinux() call
install: simplification
delta: draw arrows with draw_special_char()

Let's unify generation of unicode chars at one place.

Also, don't add an extra space into chars we print, except for the tree
chars where this is really necessary.
use new name DRAW_TREE_VERTICAL

Was renamed in 6b01f1d3911bd7c7eadbb8a3b4375bd3ac05c98f