[MRH] Updated HirearchyTreeNode.java
[MRH] Updated HirearchyTreeNode.java

RMG was throwing an error that a FunctionalGroupCollection could not be cast as a FunctionalGroup.  I have updated the source code to check if the current instance is of a FunctionalGroup or a FunctionalGroupCollection.

jwallen/RMG-Java,faribas/RMG-Java,faribas/RMG-Java,rwest/RMG-Java,KEHANG/RMG-Java,KEHANG/RMG-Java,KEHANG/RMG-Java,nyee/RMG-Java,enochd/RMG-Java,enochd/RMG-Java,nyee/RMG-Java,ReactionMechanismGenerator/RMG-Java,enochd/RMG-Java,connie/RMG-Java,ReactionMechanismGenerator/RMG-Java,nyee/RMG-Java,connie/RMG-Java,KEHANG/RMG-Java,keceli/RMG-Java,keceli/RMG-Java,ReactionMechanismGenerator/RMG-Java,keceli/RMG-Java,rwest/RMG-Java,connie/RMG-Java,jwallen/RMG-Java,rwest/RMG-Java,jwallen/RMG-Java,faribas/RMG-Java,nyee/RMG-Java,keceli/RMG-Java,nyee/RMG-Java,ReactionMechanismGenerator/RMG-Java,connie/RMG-Java,KEHANG/RMG-Java,rwest/RMG-Java,jwallen/RMG-Java,enochd/RMG-Java,rwest/RMG-Java,keceli/RMG-Java,connie/RMG-Java,faribas/RMG-Java,nyee/RMG-Java,keceli/RMG-Java,enochd/RMG-Java,jwallen/RMG-Java,jwallen/RMG-Java,enochd/RMG-Java,ReactionMechanismGenerator/RMG-Java,KEHANG/RMG-Java