Check for unset RDBASE environment variable.
Check for unset RDBASE environment variable.

This would crash with a null pointer exception before.
Probably should check that it's set to the correct thing, but
at least we now check that it's not null.

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