* return 206 for every ranged response - fixes#494
(cherry picked from commit 92eec2178f)
* detect size of remote files - fixes#494
without this, remote files are assumed to have size 0 (even if we just
downloaded them!) and the range-related code won't run
(cherry picked from commit 960f4fcff7)
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Co-authored-by: dakkar <dakkar@thenautilus.net>
7cf0c18f83
