Fix potential deadlock in signal_set implementation.

svn path=/trunk/boost/asio/; revision=84482
Fix error in acceptor example. Refs #8421

svn path=/trunk/boost/asio/; revision=84483
Fix waitable timer documentation. Refs #8602

svn path=/trunk/boost/asio/; revision=84484
Add assertions that num_buckets_ is non-zero. Refs #7739

svn path=/trunk/boost/asio/; revision=84485
Automatically disable SSL compression.

To mitigate the risk of certain attacks, SSL compression is now disabled
by default. To enable, you can use the new ssl::context::clear_options()
function like so:

  my_context.clear_options(asio::ssl::context::no_compression);

svn path=/trunk/boost/asio/; revision=84486
Fix bug on Windows where certain operations might generate an error_code with
an invalid (i.e. NULL) error_category. Refs #8613

svn path=/trunk/boost/asio/; revision=84487
Fix problem in #warning directive. Refs #7939

svn path=/trunk/boost/asio/; revision=84488