Major Description
Unfortunately, Maven command-line parameters cannot be used to override configuration options (only to provide defaults), so with the current Math POMs it's not possible to change the minimum Clirr severity without editting pom.xml
The patch defines a property with the name minSeverity which defines the default value, and uses it in the configuration section.
This allows the user to override minSeverity on the command-line, and will continue to work even if the <minSeverity> configuration is ever dropped.