packaging: Add implicit exports into __init__.py (#531)

Fixes: #530

Author: ssbarnea

src/libtmux/__init__.py

@@ -13,3 +13,18 @@
 from .server import Server
 from .session import Session
 from .window import Window
+
+__all__ = (
+    "Pane",
+    "Server",
+    "Session",
+    "Window",
+    "__author__",
+    "__copyright__",
+    "__description__",
+    "__email__",
+    "__license__",
+    "__package_name__",
+    "__title__",
+    "__version__",
+)