This allows procedures and event hooks to have more flexible signatures.
Along the lines of:
```python
@when(SomeEvent)
def hook(event):
...
@when(SomeOtherEvent)
def hook2():
...
```
Instead of supporting only the full context spec:
```python
@when(SomeEvent)
def hook(event, **ctx):
...
```
Closes: #400
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.