starting to write docs, taking decisions on public api

examples/tutorial_basics_summary.py

@@ -0,0 +1,18 @@
+from bonobo import Graph, ThreadPoolExecutorStrategy
+
+
+def yield_from(*args):
+    yield from args
+
+
+# Represent our data processor as a simple directed graph of callables.
+graph = Graph(
+    lambda: (x for x in ('foo', 'bar', 'baz')),
+    str.upper,
+    print, )
+
+# Use a thread pool.
+executor = ThreadPoolExecutorStrategy()
+
+# Run the thing.
+executor.execute(graph)