qlsdup svn_code

prevent memleak on cancel of finding dupes

- added possibility to cancel processing
- cleanly exit dupe-search-thread when exiting application during
processing

- fixed remaining overhead count when all instances of a file
are deleted
- try to prevent missing non-deleted items after deleting large set of
duplicates

sort list of duplicates to have consistent result display for many
duplicates in a set

remove unnecessary files

- fix executable name
- improve compare performance (read & compare larger block)
- improve perfomance building result tree
- update excess usage when removing / linking duplicates

initial version