Added Checkstyle to build process and fixing checkstyle to all com.src.jpexs classes

libsrc/ffdec_lib/src/com/jpexs/decompiler/graph/GraphPartChangeException.java

@@ -23,6 +23,7 @@ import java.util.List;
  * @author JPEXS
  */
 public class GraphPartChangeException extends Exception {
+
     private final int ip;
     private final List<GraphTargetItem> output;
 
@@ -39,5 +40,4 @@ public class GraphPartChangeException extends Exception {
         return output;
     }
 
-
 }