Reload gunicorn on CSS/JS changes.

assetcache hashes files on worker startup. We don't really mind a
worker reload on asset changes, since that's no worse than the old
setup with incrementing numbers. But to make this work smoothly,
we listen for changes to the CSS/JS dirs and reload on change.

gunicorn.conf.py

@@ -28,3 +28,16 @@ def worker_abort(worker):
 	import os
 	os.abort()
 
+def config_reload_extra_files():
+	import os
+	extra_files = []
+	asset_dirs = ['files/assets/css/', 'files/assets/js/']
+
+	for dir in asset_dirs:
+		fnames = os.listdir(dir)
+		paths = map(lambda x: dir + x, fnames)
+		extra_files.extend(paths)
+
+	return extra_files
+
+reload_extra_files = config_reload_extra_files()