Updated default config.yaml.

The new configuration:

- Enables `backend.http` by default
- Removes the extra `config.auto.yaml` dependency
- Includes many more examples, lots of updates for existing examples,
  and extensive comments.

examples/config/hook.py

@@ -0,0 +1,49 @@
+# A more versatile way to define event hooks than the YAML format of `config.yaml` is through native Python scripts.
+# You can define hooks as simple Python functions that use the `platypush.event.hook.hook` decorator to specify on
+# which event type they should be called, and optionally on which event attribute values.
+#
+# Event hooks should be stored in Python files under `~/.config/platypush/scripts`. All the functions that use the
+# @hook decorator will automatically be discovered and imported as event hooks into the platform at runtime.
+
+# `run` is a utility function that runs a request by name (e.g. `light.hue.on`).
+from platypush.utils import run
+
+# @hook decorator
+from platypush.event.hook import hook
+
+# Event types that you want to react to
+from platypush.message.event.assistant import (
+    ConversationStartEvent,
+    SpeechRecognizedEvent,
+)
+
+
+@hook(SpeechRecognizedEvent, phrase='play ${title} by ${artist}')
+def on_music_play_command(event, title=None, artist=None, **context):
+    """
+    This function will be executed when a SpeechRecognizedEvent with `phrase="play the music"` is triggered.
+    `event` contains the event object and `context` any key-value info from the running context.
+    Note that in this specific case we can leverage the token-extraction feature of SpeechRecognizedEvent through
+    ${} that operates on regex-like principles to extract any text that matches the pattern into context variables.
+    """
+    results = run(
+        'music.mpd.search',
+        filter={
+            'artist': artist,
+            'title': title,
+        },
+    )
+
+    if results:
+        run('music.mpd.play', results[0]['file'])
+    else:
+        run('tts.say', "I can't find any music matching your query")
+
+
+@hook(ConversationStartEvent)
+def on_conversation_start(event, **context):
+    """
+    A simple hook that gets invoked when a new conversation starts with a voice assistant and simply pauses the music
+    to make sure that your speech is properly detected.
+    """
+    run('music.mpd.pause_if_playing')