Added a simple initial version of a context mirror object which just holds the user data from the context, and does not preserve handle identity.

A script object now holds a reference to the custom data from the context it was compiled in. This data is included in the debugger protocol for scripts.

Changed the serialization for the scripts command to use the mirror objects instaed of custom serialization. This included passing options from the debugger request to the serializer for including the full source of scripts in the response.
Review URL: http://codereview.chromium.org/111001

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1877 ce2b1a6d-e550-0410-aec6-3dcde31c8c00