can be given as argument to launcher

OutputPathGenerator.java
    added parameter identifier to createPaths method
DefaultOutputPathGenerator.java
    identifier is made part of outer path
    updated test
LauncherArgs.java
    added identifier as option
Launcher.java
    identifier is passed to output path generator
    updated test
SimulationLooper, DefaultSimulationLooper.java
    output paths are passed as Iterator
    updated test