Add '-version' as command line option (#427)

* Add '-version' as command line option

* Print version via System.out for better formatting

* Add '-v' option for version

dbms/src/main/java/org/polypheny/db/PolyphenyDb.java

@@ -118,6 +118,9 @@ public class PolyphenyDb {
     @Option(name = { "-c", "--config" }, description = "Path to the configuration file", type = OptionType.GLOBAL)
     protected String applicationConfPath;
 
+    @Option(name = {"-v", "--version"}, description = "Current version of Polypheny-DB")
+    public boolean versionOptionEnabled = false;
+
     // required for unit tests to determine when the system is ready to process queries
     @Getter
     private volatile boolean isReady = false;
@@ -142,6 +145,11 @@ public static void main( final String[] args ) {
                 return;
             }
 
+            if ( polyphenyDb.versionOptionEnabled ) {
+                System.out.println("v" + polyphenyDb.getClass().getPackage().getImplementationVersion());
+                return;
+            }
+
             polyphenyDb.runPolyphenyDb();
         } catch ( Throwable uncaught ) {
             if ( log.isErrorEnabled() ) {