Document the Open edX package.

openedx/__init__.py

+"""
+This is the root package for Open edX. The intent is that all importable code
+from Open edX will eventually live here, including the code in the lms, cms,
+and common directories.
+
+Note: for now the code is not structured like this, and hence legacy code will
+continue to live in a number of different packages. All new code should be
+created in this package, and the legacy code will be moved here gradually.
+"""

openedx/core/__init__.py

+"""
+This is the root package for all core Open edX functionality. In particular,
+the djangoapps subpackage is the location for all Django apps that are shared
+between LMS and CMS.
+
+Note: the majority of the core functionality currently lives in the root
+common directory. All new Django apps should be created here instead, and
+the pre-existing apps will be moved here over time.
+"""