Updated build environment
Fixed handling of non-string collection properties and undefined method return values

- Collection properties with values false or null had not been exported (but
  should be).
- Collection properties which exist, but have a value of undefined, have thrown
  an exception. Defined properties never should. Even so, they must not be
  exported. In accordance with the JSON spec, they are ignored.
- The same applies to methods which return undefined.
Updated build