Duplicate Files Finder 0.8.0 released

This release mainly adds symbolic link support for Windows, many GUI changes, improved search support, and improved compiling support.

The changes in detail:
- made the build more tolerant to different build environments
- added symbolic link support for Windows
- improved search options (masks with ';' (windows) or ':' (unix) in it are allowed; exclude masks were introduced)
- many gui changes
- created dll with common code
- program icon for Windows
- progress display improved
- and many other changes