[PDI-4325] Spoon carte status is not showing in Japanese when Japanese is selected

1)  core/src/org/pentaho/di/cluster/HttpUtil.java
Refactored, added methods to properly handle byte-to-String transformations.

2)  core/test-src/org/pentaho/di/cluster/HttpUtilTest.java 
junit test added

3)  engine/src/org/pentaho/di/cluster/SlaveServer.java
replaced redundant code

4) engine/src/org/pentaho/di/www/GetJobStatusServlet.java
engine/src/org/pentaho/di/www/GetTransStatusServlet.java

5) ui/src/org/pentaho/di/core/dnd/XMLTransfer.java
added byte-wise transformation