Adding messages array to checker.
Moved type check into add_message.
Remove messages clear from .clear.
Require explicit calls to add_message.
Refactor add_messages to be string based.
Add rspec helpers for testing.
Add additional context tests.
Do not show an empty messages list.
Add an add_message example to README.
[ci skip]
Add a note that numerics are valid message values.
[ci skip]
Add message details to changelog.
[ci skip]