Fix issues so v8 could be built as a DLL.

-. get rid of all the compiler warning by moving dllexport/dllimport
to the individual members for classes which have inline members.

-. update v8 gyp to build v8.dll for chromium multi-dll version (win
and component==shared_library)

Note: most of the code are contributed by sjesse.

Code review URL: http://codereview.chromium.org/2882009/show

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5006 ce2b1a6d-e550-0410-aec6-3dcde31c8c00