Log Message:
rtorrent: updated to 0.15.1

0.15.1

Resolved scgi software crash with SIGPIPE exception.
Various build stability improvements.
Change _sync* to std::atomic for cross platform compatibility.
Resolved a crash with the curl stack during shutdown.
Resolve Wclass-memaccess compile warning with std::memset.
Fixed d.group.name returning the wrong value.
Fixed compatibility checks for file types.