Merge pull request #26 from zde/master

Sanitize progresscb.
Remove local RPM spec file and add link to the Fedora's one to README.md
Downloading: LRO_MAXSPEED has effect over whole downloading, it is not per target max speed anymore.
Bumpt to 1.5.1
Better download resume logic
Bump to 1.5.2
Fix one typedef and possible uninitialized value
Ignore rsync url silently
Support for byterange of download (RhBug: 1058777)