add block_forever example

update example READMEs

add script entry point for block_forever example
add poe task block-forever

scripts.py

@@ -6,3 +6,11 @@ from pathlib import Path
 def ex_events():
     scriptpath = Path.cwd() / 'examples' / 'events' / '.'
     subprocess.run([sys.executable, str(scriptpath)])
+
+
+def ex_block_forever():
+    scriptpath = Path.cwd() / 'examples' / 'block_forever' / '.'
+    try:
+        subprocess.run([sys.executable, str(scriptpath)])
+    except KeyboardInterrupt:
+        sys.exit(0)