ADDED: util/Parallel.java

 * Original source:
   https://github.com/pablormier/parallel-loops/blob/master/src/main/java/es/usc/citius/common/parallel/Parallel.java
CHANGED: add features into Parallel.java
wip: parallel

 * Proof-of-concept code for assets/objects/* hash checking
 * Proof-of-concept code for assets/virtual/foo hash checking