New (experimental) option 'bmp' in borotool.

This option is conceived as a visual cue for the balancing of a tree.
Now it's on text on stdout, but for tree depths higher than 5 it's
useless. To be done on a 'real' bitmap.
New borotool option 'fdict'.
New borotool option 'lexport'.
New borotool function 'flist'.
Changed test-20140912 to use fdict instead of import.