Release 4.1.1

Release 4.1.1 comes with a new optional, experimental strategy how group interfaces are generated by the group-contract plugin. This should fix many problems with using the plugin in environments other than from the command line or via the jaxb-maven-plugin, because it doesn't do any pre-XSD-parsing voodoo anymore. Command-line parameter order also doesn't matter anymore.
There are also bugfixes to the "choice expansion" mechanism: In some cases, alternative child objects built by sub-builders were lost in the final build phase.