Error codes

# CAL10N error codes and their meanings

### Missing `@BaseName` annotation in enum type [...].

The @BaseName annotation is mandatory when an enum type is used in conjuction with MessageConveyor to retreive localized messages. See the user manual as well as the javadocs for BaseName annotation for more details.

### Missing @LocaleData annotation in enum type [...].

If an enum type and its associated bundles are to be verified via the maven-cal10n-plugin or via a single unit test, then the enum type needs to be annotated with LocaleData.

### Missing `<enumTypes>` element.

The `<enumTypes>` is a required parameter of the maven-cal10n-plugin. Please refer to the section on maven-cal10n-plugin in the user manual for more details.