Improve exception messages
Merge pull request #3981 from neeckeloo/fix-exception-messages

Improve exception messages
[#3981] Fixes to exception strings

- No need to use `__CLASS__::__METHOD__` in exception strings;
  `__METHOD__` already contains the class.
- Changes to quotes in exception messages required changes to two unit
  tests
[#3981] CS fixes

- EOF ending
Merge branch 'hotfix/3981'

Close #3981