Refactor all examples:

fix #575, fix #604, fix #608, fix #634, fix #712

All examples are rewritten:

* Using Best Practices
* Mostly self-contained
* New examples to complete the feature matrix
* The server-framework example is removed

example/advanced/server-flex/CMakeLists.txt

@@ -0,0 +1,26 @@
+#
+# Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#
+# Official repository: https://github.com/boostorg/beast
+#
+
+GroupSources(include/boost/beast beast)
+GroupSources(example/common common)
+GroupSources(example/advanced/server-flex "/")
+
+add_executable (advanced-server-flex
+    ${BOOST_BEAST_INCLUDES}
+    ${PROJECT_SOURCE_DIR}/example/common/detect_ssl.hpp
+    ${PROJECT_SOURCE_DIR}/example/common/server_certificate.hpp
+    ${PROJECT_SOURCE_DIR}/example/common/ssl_stream.hpp
+    ${PROJECT_SOURCE_DIR}/example/common/write_msg.hpp
+    Jamfile
+    advanced_server_flex.cpp
+)
+
+target_link_libraries (advanced-server-flex
+    ${OPENSSL_LIBRARIES}
+    )

example/advanced/server-flex/Jamfile

@@ -0,0 +1,21 @@
+#
+# Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#
+# Official repository: https://github.com/boostorg/beast
+#
+
+project
+    : requirements
+    <library>ssl
+    <library>crypto
+    ;
+
+exe advanced-server-flex :
+    advanced_server_flex.cpp
+    :
+    <variant>coverage:<build>no
+    <variant>ubasan:<build>no
+    ;