[Fix][Cont] Added Unit test for RSE-load negative mass bug.
  - Added Test case in TestMotorLoader.java
  - Added Test load file 'test3.rse' which would previously raise an IOException on load.
  - Added this test case to the 'testGeneralMotorLoader' method as well.
  - Adjusted the digest string so that 'test3.rse' will pass the unit tests.
  - TestMotorLoader currently passes 5/5 unit tests.
 re-apply patch 5c0d9eb... which was clobbered by mistake
[Fix][Cont] Added Unit test for RSE-load negative mass bug.

  - Added Test case in TestMotorLoader.java
  - Added Test load file 'test3.rse' which would previously raise an IOException on load.
  - Added this test case to the 'testGeneralMotorLoader' method as well.
  - Adjusted the digest string so that 'test3.rse' will pass the unit tests.
  - TestMotorLoader currently passes 5/5 unit tests.