Minor refactorings

This pull request contains some refactorings that occured to me while working on another feature branch:

The only functional change is that `JARFileMaker` is now a builder.  Beyond that, I added logging or tighter exception handling to `YarnJobSubmissionHandler`, `YARNResourceLaunchHandler`, `YARNResourceReleaseHandler`, `YarnConfigurationConstructor`, `EvaluatorManager`, `EvaluatorManagerFactory` and `Launcher`.
should we check for `HADOOP_CONF_DIR` first?