Unclear error message when execute jar without option

[aPlacuzzi]

Execute jar without option should produce an error message that explains how to execute the different modalities.

The actual message is the following:

$ java -jar alchemist-full-9.3.0-devvl+8dafd6ea0-all.jar
17:35:21.386 [main] ERROR it.unibo.alchemist.Alchemist - No valid launchers for AlchemistExecutionOptions(configuration=null, headless=false, variables=[], batch=false, export=null, distributed=null, graphics=null, help=false, interval=1.0, server=null, parallelism=4, endTime=Infinity)
17:35:21.390 [main] WARN  it.unibo.alchemist.Alchemist - Available launchers: [Alchemist execution on a grid system, Alchemist headless runner, Alchemist grid computing server, Alchemist graphical simulation]
17:35:21.390 [main] ERROR it.unibo.alchemist.Alchemist - Available launchers: [Alchemist execution on a grid system, Alchemist headless runner, Alchemist grid computing server, Alchemist graphical simulation]
17:35:21.390 [main] ERROR it.unibo.alchemist.Alchemist - DistributedExecution: Alchemist execution on a grid system requires a simulation file
17:35:21.390 [main] ERROR it.unibo.alchemist.Alchemist - HeadlessSimulationLauncher: Alchemist headless runner requires a simulation file
17:35:21.390 [main] ERROR it.unibo.alchemist.Alchemist - IgniteServerLauncher: No Ignite configuration file specified
17:35:21.390 [main] ERROR it.unibo.alchemist.Alchemist - SingleRunSwingUI: Alchemist graphical simulation requires a simulation file

[DanySK]

Fixed in 5584ed4 if the build succeeds