Merge pull request #259 from jktjkt/docs

docs: Show a pretty picture of GNPy in action

Thanks to Esther for suggesting this, and to Gert and Esther for their reviews.

README.rst

@@ -1,3 +1,8 @@
+.. image:: docs/images/GNPy-banner.png
+   :width: 100%
+   :align: left
+   :alt: GNPy with an OLS system
+
 ====================================================================
 `gnpy`: mesh optical network route planning and optimization library
 ====================================================================
@@ -117,16 +122,13 @@ fully-functional programs.
     specific, delineated use cases to drive requirements for future
     development.*
 
-**To get started, run the main transmission example:**
-
-    **Note**: *Examples should be run from the examples/ folder.*
-
-.. code-block:: shell-session
+This example demonstrates how GNPy can be used to check the expected SNR at the end of the line by varying the channel input power:
 
-    $ pwd
-    /path/to/oopt-gnpy
-    $ cd examples
-    $ python transmission_main_example.py
+.. image:: https://telecominfraproject.github.io/oopt-gnpy/docs/images/transmission_main_example.svg
+   :width: 100%
+   :align: left
+   :alt: Running a simple simulation example
+   :target: https://asciinema.org/a/252295
 
 By default, this script operates on a single span network defined in
 `examples/edfa_example_network.json <examples/edfa_example_network.json>`_
@@ -137,8 +139,7 @@ example, to use the CORONET Global network defined in
 
 .. code-block:: shell-session
 
-    $ cd examples
-    $ python transmission_main_example.py CORONET_Global_Topology.json
+    $ ./examples/transmission_main_example.py examples/CORONET_Global_Topology.json
 
 It is also possible to use an Excel file input (for example
 `examples/CORONET_Global_Topology.xls <examples/CORONET_Global_Topology.xls>`_).