Improve command-line error handling in XMvn Resolve
Add support for classifiers to resolvers
Fix incorrect parameter order in DefaultArtifact constructor
Start worker threads as daemons

This is important so that JVM exits cleanly when only worker threads
remain alive.
Deprecate DependencyMap.addMapping(SSSSS)
Extend installer settings model

This adds classifiers, extensions and stereotypes to installer
settings in configuration model.
[test] Update tests for classifiers et al.
Extend stereotype support in configuration model
[test] Update tests to work with new stereotypes
Redesign XMvn installer almost from scratch
Install a custom bin/xmvn script
Add integration tests to POM
[it] Add empty-project integration test
[it] Add compiler-source-1.5 integration test
[it] Add override-compiler-source integration test
Fix extension and classifier handling in DepmapReader
Add namespace support in auto-requires/provides
[aux] Don't reformat integration tests