printed Java rewrite engine statistics only when --statistics is on
fixed ConcreteCollectionVariable#matchConcreteSize
addressed Andrei's comment
Merge branch 'master' into fixing-issue-979
Merge branch 'master' into fixing-issue-987
Merge pull request #992 from yilongli/fixing-issue-987

printed Java rewrite engine statistics only when --statistics is on
Merge pull request #989 from yilongli/fixing-issue-979

fixed ConcreteCollectionVariable#matchConcreteSize
separate java backend out into separate maven module / k plugin
fix copyright
move java-backend-only dependencies to new pom
create shared launch configuration for K
update .gitignore