TODO

========================= GUI
[x] menubar (fring,help)
    [x] refresh
    [x] save to file
    [x] select directory
    [x] show hidden files
    [x] "about" dialogue
    [x] open parent folder

[x] click on folder -> open it
[x] show busy cursor while walking dir tree
[x] do not show black backrgound when app starts up
[ ] don't reload the busy cursor when it's already set

========================= DISPLAY
[x] display total in ring center 
[x] restore the rainbow
[D] always render text on top
[-] make sure that filenames are always visible
[ ] cut down loooong directory names in link labels

========================= FOLDER READING
[x] merge back c_walker
[x] sort subdirectories
[ ] don't re-walk the tree when opening a subdirectory
[ ] don't use size, use blocks of 512k instead
    (this will solve a couple of long/int bugs)

========================= DOCUMENTATION
[ ] write README