Add note to LabelQueryJSOTest

This test fails in development mode, but passes in production mode. I
think this is a Java-JavaScript language issue. See:
http://www.gwtproject.org/doc/latest/DevGuideCodingBasicsCompatibility.html#language.
Add LabelJSO unit test

Also fixed minor typo in LabelQueryJSOTest.
Add ModelMetadataJSO unit test

Also make minor adjustments to LabelJSOTest.
Add ParameterJSO unit test
Add ValueJSO unit tests for types string, int, and float

Still need to devise tests for types choice and files.
Add ValueJSO unit tests for types choices and file