RssReader::Process: fix: read unknown length files correctly
ScraperUrl::Get: fix: avoid race conditions
Merge pull request #3514 from Karlson2k/scraperurl_fix_01

ScraperUrl::Get: fix: avoid race conditions
Fix a warning on windows.
Fix Player.play crash on Windows due to trying to assign NULL to a reference.
Merge pull request #3513 from Karlson2k/rss_reader_fix_01

RssReader::Process: fix: read files with unknown length correctly