TenjintShell.atexit_operations

TenjintShell.atexit_operations()

This will be executed at the time of exit.

Cleanup operations and saving of persistent data that is done unconditionally by IPython should be performed here.

For things that may depend on startup flags or platform specifics (such as having readline or not), register a separate atexit function in the code that has the appropriate information, rather than trying to clutter