Remove the need for OpenSSL in examples that don't use it

close #1524

It is now possible to compile examples without OpenSSL. Examples that
do require OpenSSL will be omitted.

Signed-off-by: Damian Jarek <damian.jarek93@gmail.com>

test/Jamfile

@@ -24,6 +24,7 @@ project /boost/beast/test
     <define>BOOST_BEAST_ALLOW_DEPRECATED
     <define>BOOST_BEAST_TESTS
     <define>BOOST_ASIO_SEPARATE_COMPILATION
+    <library>/boost/beast//static_ssl_asio
     ;
 
 path-constant ZLIB_SOURCES :

test/lib_beast.cpp

@@ -12,7 +12,6 @@
 
 // BOOST_ASIO_SEPARATE_COMPILATION for asio
 #include <boost/asio/impl/src.hpp>
-#include <boost/asio/ssl/impl/src.hpp>
 
 // BOOST_BEAST_SPLIT_COMPILATION for beast
 #include <boost/beast/src.hpp>

test/lib_ssl.cpp

@@ -0,0 +1,15 @@
+//
+// Copyright (c) 2016-2019 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
+//
+
+// This file is used to build a static library with
+// asio and beast definitions, to reduce compilation time.
+
+// BOOST_ASIO_SEPARATE_COMPILATION for asio::ssl
+
+#include <boost/asio/ssl/impl/src.hpp>