implementation async socks proxy

Signed-off-by: Jack <jack.wgm@gmail.com>
add vc2008 project for test proxy

Signed-off-by: Jack <jack.wgm@gmail.com>
rename avhttp-vc2005 to sync_proxy_test-vc2005

Signed-off-by: Jack <jack.wgm@gmail.com>
add async_proxy_test.cpp

Signed-off-by: Jack <jack.wgm@gmail.com>
add vc2005 test project

Signed-off-by: Jack <jack.wgm@gmail.com>
update test

Signed-off-by: Jack <jack.wgm@gmail.com>
improve socks proxy

Signed-off-by: Jack <jack.wgm@gmail.com>