Fix issue #43 and update cindex.py

Commit 774a936 is a fix for issue #43. I am not sure why this change was made (the commit message is not helpful in that regard).

The other changes bring cindex.py up-to-date with the current clang master version. I have tested this on my own code (https://github.com/rhdunn/cainteoir-engine). Specifically:

Commit 0c1cf77 creates a cldoc/clang/cindex-updates.patch containing the cldoc changes to cindex.py, and a README.md documenting where the source of cindex.py originates. This commit does not change cindex.py.

Commit 9728c1d removes the cldoc changes that remove functions from the functionList. This is needed as some cindex APIs are dependent on those methods.

Commit ecd3dde includes changes that support TypeKind 114 to 117, but before the introduction of cindex.AccessSpecifier. This removes a hunk in the patch.

Commit d534720 only includes the cindex.AccessSpecifier change from clang, and makes cldoc use it instead of cindex.CXXAccessSpecifier.

Finally, commit 009c326 updates cindex.py to the latest version from clang.