Improvements to increase code coverage:

* Don't include the test code in coverage reports
* Add test code for missing coverage

Other:

* Improve the README.md
* Fix warning in sha1_context
* Tidy up the examples use of namespaces
* Various fixes to documentation and javadocs

test/websocket/websocket_sync_echo_peer.hpp

@@ -36,7 +36,6 @@ namespace websocket {
 class sync_echo_peer
 {
 public:
-    using error_code = boost::system::error_code;
     using endpoint_type = boost::asio::ip::tcp::endpoint;
     using address_type = boost::asio::ip::address;
     using socket_type = boost::asio::ip::tcp::socket;