Revert "Delete __init__.py"

This reverts commit 5603556.

yledl/__init__.py

@@ -0,0 +1,38 @@
+# This file is part of yle-dl.
+#
+# Copyright 2010-2022 Antti Ajanki and others
+#
+# Yle-dl is free software: you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Yle-dl is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with yle-dl. If not, see <https://www.gnu.org/licenses/>.
+
+from .backends import Backends
+from .downloader import YleDlDownloader
+from .exitcodes import RD_SUCCESS, RD_FAILED, RD_INCOMPLETE
+from .io import IOContext, DownloadLimits
+from .streamfilters import StreamFilters
+from .version import __version__
+from .yledl import execute_action, StreamAction
+
+__all__ = [
+    '__version__',
+    'execute_action',
+    'YleDlDownloader',
+    'StreamFilters',
+    'DownloadLimits',
+    'IOContext',
+    'Backends',
+    'StreamAction',
+    'RD_SUCCESS',
+    'RD_FAILED',
+    'RD_INCOMPLETE',
+]