bug:"remove duplicates" works incomplete with duplicates count > 1

What steps will reproduce the problem?
1.Add same file in playlist multiple times, at least three (ten better)
2.Try "remove duplicates" button on the playlist edit ("-"->"remove duplicates")
3.Enjoy :)

What is the expected output? What do you see instead?

I excepting the all duplicates will be ridden out of my playist. 
But what I see: with ten existances, after this button remains three 
existances, with three existances remain two, and with two, at least, i get 
single existance.

What version of the product are you using? On what operating system?

qmmp 0.5.2 with qt 4.7.4-r1 on gentoo x86 3.0.4

Please provide any additional information below.

I think calling of this method need to be wrapped in a while or until statement.
Cheers, and thanks to the development and testing team. It will be a best 
player, I sure. :)

Original issue reported on code.google.com by dm.dutch...@gmail.com on 18 Jan 2012 at 12:20

degeron / qmmp

bug:"remove duplicates" works incomplete with duplicates count > 1 #516