Loosen return type restrictions on ModuleProviders.

Instead of dealing with DynObjects or JSObjects, the ModuleProvider
classes should make no assumptions about the type of object that is
exported. This allows for modules to export Java classes, for example.

    // program.js
    var BufferType = require('java_buffer');
    var buffer = new BufferType();

    // java_buffer.js
    module.exports = me.tiger.tony.Buffer;