External Array renaming and boilerplate scrapping

Replaced symbolic names with correct JS name (byte -> int8, unsigned int -> uint32 etc).
Using macros to scrap the boilerplate
BUG=
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/145133013

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18835 ce2b1a6d-e550-0410-aec6-3dcde31c8c00