#39 Make native-method API environment based like JNDI

[Rick McGuire]

The current native method API relies on direct linking to the individual APIs. The APIs would version better and work more cleanly if they operated off of a call vector like the Java JNI APIs. In particular, this would allow code like the scripting code to attach a thread and have a persistent enviroment to allow objects to be created or messages to be dispatched to objects without needing to call ooRexx code first and get a callback.