Updated readme

Added all sphinx headings.

Author: paulross

README.md

@@ -4,4 +4,8 @@ Examples of reliable coding of Python 'C' extensions by Paul Ross.
 
 ## Contents:
 
-[Introduction to reference counts](doc/sphinx/source/refcount.rst).
+Introduction to [reference counts](doc/sphinx/source/refcount.rst) in Python C extensions.
+Managing [exceptions](doc/sphinx/source/exceptions.rst).
+A [canonical function pattern](doc/sphinx/source/canonical_function.rst) for C extensions.
+Handling [function arguments](doc/sphinx/source/parsing_arguments.rst).
+Creating, setting and getting [module globals](doc/sphinx/source/module_globals.rst).