Add support for handling more types in JSONSerializer

add support for all types of values that NodeContainer.setProperty() can handle to JSONSerializer: booleans, floats, doubles, shorts, bytes, String arrays, and all primitive arrays.

add some code to JSONSerializerTest that would have thrown IllegalArgumentException about unknown value type otherwise

(I could not get my test to pass against the 1.9 master branch.  Something must have changed in 1.9 about modifying the graph data in the unit test.)