Fix for #1994

lib/pkg_resources.py

@@ -0,0 +1,11 @@
+# Stub file. Not affiliated with the original 'pkg_resource.py' included in the
+# 'setuptools' package.
+
+def iter_entry_points(group, name=None):
+    """
+    Stub method to make APScheduler happy. This method is only imported in
+    'lib/apscheduler/schedulers/base.py' to autodetect triggers, executors and
+    job stores. Headphones does not use this functionality, so it just returns
+    an iterator of an empty dict.
+    """
+    return iter(dict())