release: 0.4.8

Merge pull request #2 from KrugerHeavyIndustries/feat/workoff

use dispatcho workoff()

Merge pull request #1 from KrugerHeavyIndustries/update/unique_ptr

std::auto_ptr -> std::unique_ptr

update copyright

version 0.4.3

version 0.4.2

version 0.4.1

initial support for multi-threaded download

working delete_file_version

fix thinko/typo _ => .