Environment is (currently) represented as an Array[String]
Remove logback dependency

slf4j allows the user to choose her own implementation, so including
logback isn't necessary.
Merge pull request #6 from dln/logging-dependencies

Issue #6: Remove logback dependency
Merge pull request #5 from dln/env-fix

Issue #4: Environment is (currently) represented as an Array[String]
Merge branch 'master' into java-7