* Implement checks for messages being raised with exceptions
(Fixes#1080)
* Add self.assertRaisesWithMessage method to relevant exercise tests
- Uses self.assertRaisesRegex
- Checks only for the presence of a message, not content
* Add meaningful messages to failing examples
* octal: Switch to using a context manager for exception tests
* Add note regarding error messages to the insert
* simple-linked-list: Move hints.md to correct location
* simple-cipher: Remove extra whitespace from lines
* collatz-conjecture: Update hints.md
* Regenerate README to include exceptions section
