Create CheckStyle project and base style rules
Extend CheckStyle to allow excluding some style rules in tests
Extend CheckStyle to allow verifying for an empty copyright
Introduce a CheckStyle rule to ban import statements from specific packages
Enable CheckStyle for the LuceneV3 module
Apply code style fixes as detected by the new CheckStyle rules on Lucenev3
Re-synchronize testsuite for Lucene Directory V4 vs. v3 (CheckStyle and other missing improvements)