Override protected methods on java objects

Searching for protected methods in the class hierarchy so they can be defined in the bytecode
following the current behavior for public methods.
Create stack trace upon NativeError.
All Javascript errors always have a stack attribute.
Don't need to define stack on JSObjects now.
Removed unused constructor, tidied fields.
Fixed imports.
Merge branch 'create-stack-on-error-construction'
Initial impl and tests for __defineGetter__ and __defineSetter__. Stub __lookupGetter__
Use existing PropertyDescriptor in Define?etter
Ignore failing test
Override protected methods on java objects

Searching for protected methods in the class hierarchy so they can be defined in the bytecode
following the current behavior for public methods.
Create stack trace upon NativeError.
All Javascript errors always have a stack attribute.
Don't need to define stack on JSObjects now.
Removed unused constructor, tidied fields.
Fixed imports.
Make new PropertyDescriptors configurable in  Define?etter classes
Reference this.bar - as it should have been.
Implement __lookupGetter__ and __lookupSetter__ for rhino compat.
Account for <module>/lib/<module>.js in FilesystemModuleProvider