merged changes from trunk

git-svn-id: http://libtorrent.googlecode.com/svn/branches/libtorrent_aio@6107 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
fix some bugs in connection_tester and add feature to create dummy test torrents

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@6108 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
added async_add_torrent for increased performance when adding many torrents (no documentation yet though)

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@6109 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
optimization to default_storage to not stat() every file multiple times on startup

git-svn-id: http://libtorrent.googlecode.com/svn/branches/libtorrent_aio@6110 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
merged changes from trunk

git-svn-id: http://libtorrent.googlecode.com/svn/branches/libtorrent_aio@6111 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
fix bug in flush_cache_blocks

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@6112 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
optimize string handling when parsing .torrents

git-svn-id: http://libtorrent.googlecode.com/svn/branches/libtorrent_aio@6113 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
make verify_resume_data use the stat cache as well, to optimize torrent loading

git-svn-id: http://libtorrent.googlecode.com/svn/branches/libtorrent_aio@6114 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
optimize torrent queue position assignment

git-svn-id: http://libtorrent.googlecode.com/svn/branches/libtorrent_aio@6115 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
post disk buffer pool uncorked events before starting to free the buffers, to save latency

git-svn-id: http://libtorrent.googlecode.com/svn/branches/libtorrent_aio@6116 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
queue position fix

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@6117 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
use stat cache in write_resume_data as well

git-svn-id: http://libtorrent.googlecode.com/svn/branches/libtorrent_aio@6118 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
minor optimization in save_resume_data

git-svn-id: http://libtorrent.googlecode.com/svn/branches/libtorrent_aio@6119 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
log number of asio messages passed through the queue per second (to track down performance issue)

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@6121 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
log buffer sizes passed to read() and write() at the socket layer (to identify performane problems)

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@6123 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
log CPU usage of network thread

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@6125 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
windows version of CPU time measurement

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@6126 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
fix overflow issue when determining number of outstanding bytes

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@6127 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
optimize socket send buffers a bit

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@6129 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
post disk job completions in batches to save CPU in the network thread

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@6130 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda