cancel non-critical DNS lookups when shutting down, to cut down on shutdown delay

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@10612 a83610d8-ad2a-0410-a6ab-fc0612d85776
fix sanitizer options in jamfile

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@10613 a83610d8-ad2a-0410-a6ab-fc0612d85776
fix comment formatting

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@10614 a83610d8-ad2a-0410-a6ab-fc0612d85776
merged changes from RC_1_0

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@10617 a83610d8-ad2a-0410-a6ab-fc0612d85776
we no longer support including file-hashes when creating torrents

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@10618 a83610d8-ad2a-0410-a6ab-fc0612d85776
optimize copying torrent_info and file_storage objects

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@10619 a83610d8-ad2a-0410-a6ab-fc0612d85776