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
[x] don't reload the busy cursor when it's already set

========================= DISPLAY
[x] display total in ring center 
[x] restore the rainbow
[x] cut down loooong directory names in link labels
[ ] make sure labels don't overlap
[ ] make rainbow colour depend of percent of total

========================= FOLDER READING
[x] merge back c_walker
[x] sort subdirectories
[x] don't re-walk the tree when opening a subdirectory
[x] put all the sumlists in one central place
[ ] handle directories with many many many files correctly
[ ] show hidden files by default or not?

========================= OTHER
[x] i18n support
[ ] write README
[ ] make website