Reorganize repository

* Move the project top-level CMakeLists.txt to the root of the project;
  this allows building Cyclone as part of ROS2 without any special
  tricks;

* Clean up the build options:

  ENABLE_SSL:    whether to check for and include OpenSSL support if a
                 library can be found (default = ON); this used to be
                 called DDSC_ENABLE_OPENSSL, the old name is deprecated
                 but still works
  BUILD_DOCS:    whether to build docs (default = OFF)
  BUILD_TESTING: whether to build test (default = OFF)

* Collect all documentation into top-level "docs" directory;

* Move the examples to the top-level directory;

* Remove the unused and somewhat misleading pseudo-default
  cyclonedds.xml;

* Remove unused cmake files

Signed-off-by: Erik Boasson <eb@ilities.com>

examples/roundtrip/readme.rst

@@ -0,0 +1,83 @@
+..
+   Copyright(c) 2006 to 2018 ADLINK Technology Limited and others
+
+   This program and the accompanying materials are made available under the
+   terms of the Eclipse Public License v. 2.0 which is available at
+   http://www.eclipse.org/legal/epl-2.0, or the Eclipse Distribution License
+   v. 1.0 which is available at
+   http://www.eclipse.org/org/documents/edl-v10.php.
+
+   SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
+
+Roundtrip
+==========
+
+Description
+***********
+
+The Roundtrip example allows the measurement of roundtrip duration when sending and receiving back a single message.
+
+Design
+******
+
+It consists of 2 units:
+
+- Pong: waits for messages from ping and sends the same message back.
+- Ping: Sends a message to pong and waits for its return.
+
+Scenario
+********
+
+A message is sent by the **ping** executable on the "PING" partition, which the **pong** executable is waiting for.
+The **pong** executable sends the same message back on the "PONG" partition, which the **ping** executable is waiting for.
+This sequence is repeated a configurable number of times.
+
+The **ping** executable measures:
+
+- writeAccess time: time the write() method took.
+- readAccess time: time the take() method took.
+- roundTrip time: time between the call to the write() method and the return of the take() method.
+- **ping** also calculates min/max/average statistics on these values over a configurable number of samples and/or time out period.
+
+Configurable:
+
+- payloadSize: the size of the payload in bytes.
+- numSamples: the number of samples to send.
+- timeOut: the number of seconds ping should run for.
+
+
+Running the example
+*******************
+
+It is recommended that you run ping and pong in separate terminals to avoid mixing the output.
+
+- Open 2 terminals.
+- In the first terminal start Pong by running pong.
+
+  pong usage:
+    ``./pong``
+
+- In the second terminal start Ping by running ping.
+
+  ping usage (parameters must be supplied in order):
+    ``./ping [payloadSize (bytes, 0 - 655536)] [numSamples (0 = infinite)] [timeOut (seconds, 0 = infinite)]``
+
+    ``./ping quit - ping sends a quit signal to pong.``
+  defaults:
+    ``./ping 0 0 0``
+
+- To achieve optimal performance it is recommended to set the CPU affinity so that ping and pong run on separate CPU cores,
+  and use real-time scheduling. In a Linux environment this can be achieved as follows:
+
+  pong usage:
+    ``taskset -c 0 chrt -f 80 ./pong``
+  ping usage:
+    ``taskset -c 1 chrt -f 80 ./ping [payloadSize (bytes, 0 - 655536)] [numSamples (0 = infinite)] [timeOut (seconds, 0 = infinite)]``
+
+  On Windows the CPU affinity and scheduling class can be set as follows:
+
+  pong usage:
+    ``START /affinity 1 /high cmd /k "pong.exe"``
+  ping usage:
+    ``START /affinity 2 /high cmd /k "ping.exe" [payloadSize (bytes, 0 - 655536)] [numSamples (0 = infinite)] [timeOut (seconds, 0 = infinite)]``
+