Sphinx-based documentation added

docs/examples/avg_speed.rst

@@ -0,0 +1,8 @@
+avg_speed
+=========
+
+.. literalinclude:: ../../example/avg_speed.cpp
+  :caption: avg_speed.cpp
+  :start-at: #include
+  :linenos:
+  :force:

docs/examples/hello_units.rst

@@ -0,0 +1,7 @@
+hello_units
+===========
+
+.. literalinclude:: ../../example/hello_units.cpp
+  :caption: hello_units.cpp
+  :start-at: #include
+  :linenos: