Add Python 3 modules, and more Python 2 modules.

Also, sort names alphabetically and add module docstrings.

python2/_random.py

@@ -0,0 +1,18 @@
+"""Stub file for the '_random' module."""
+# This is an autogenerated file. It serves as a starting point
+# for a more percise manual annotation of this module.
+# Feel free to edit the source below, but remove this header when you do.
+
+class Random(object):
+    def getrandbits(a: int) -> object:
+        raise ValueError()
+        raise MemoryError()
+    def getstate() -> tuple: pass
+    def jumpahead(*args, **kwargs) -> NoneType:
+        raise TypeError()
+    def random() -> float: pass
+    def seed(*args, **kwargs) -> NoneType:
+        raise MemoryError()
+    def setstate(*args, **kwargs) -> NoneType:
+        raise TypeError()
+        raise ValueError()