Add tools.jar to classpath only on Windows and Linux.

Mac OS X bundles tools.jar with classes.jar so there is no need to add
tools.jar. But on Windows and Linux, tools.jar is not bundled in rt.jar, so
tools.jar must be added to classpath separately.

See http://stackoverflow.com/questions/12409847/how-to-add-tools-jar-as-a-dynamic-dependency-in-sbt-is-it-possible
Override configuration with mode specific cofiguration.
Just get from configuration instead of get with fallback value.

Because default fallback value is managed by application.conf, get with
hardcoded fallback value is redundunt.
Extract config files from Global.
Use different paths of mongodb and zookeeper per mode.