Added the current running application as a static object.

```python
from platypush import app
```

platypush/__init__.py

@@ -5,7 +5,7 @@ Platypush
 .. license: MIT
 """
 
-from .app import Application
+from .app import Application, app
 from .config import Config
 from .context import Variable, get_backend, get_bus, get_plugin
 from .cron import cron
@@ -31,6 +31,7 @@ __all__ = [
     'Event',
     'Request',
     'Response',
+    'app',
     'cron',
     'get_backend',
     'get_bus',

platypush/app/__init__.py

@@ -1,4 +1,4 @@
-from ._app import Application, main
+from ._app import Application, app, main
 
 
-__all__ = ["Application", "main"]
+__all__ = ["Application", "app", "main"]

platypush/app/_app.py

@@ -464,10 +464,15 @@ class Application:
             self._run()
 
 
+app: Optional[Application] = None
+
+
 def main(*args: str):
     """
     Application entry point.
     """
+    global app
+
     app = Application.from_cmdline(args)
 
     try: