Add an Xcode project for V8.

This project exports two static library targets to be used by Chromium: jscre, v8

Review URL: http://codereview.chromium.org/264

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@179 ce2b1a6d-e550-0410-aec6-3dcde31c8c00