Update sphinx to latest version

[rimms]

The following error is printed when using latest version (Sphinx 1.7.8):

Could not import extension mpidl_domain (exception: cannot import name Directive)

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

Closing this issue after a prolonged period of inactivity. Please feel free to create a new issue or re-open it if you need.