Improve CommonToken cloning performance, and update documentation
ANTLR 4 targets Java 6 at minimum
Update javac options during testing to address overly verbose warnings
Merge pull request #441 from sharwell/java6-minimum

ANTLR 4 targets Java 6 at minimum
Merge pull request #442 from sharwell/test-build-warnings

Update javac options during testing to address overly verbose warnings
Merge pull request #440 from sharwell/clone-token-text

Improve CommonToken cloning performance, and update documentation
Use the fetchedEOF field to often avoid an expensive LA(1) operation in BufferedTokenStream.consume
Merge pull request #443 from sharwell/consume-opt

Use the fetchedEOF field to often avoid an expensive LA(1) operation in consume