VA-API 1.0.0 (libva 2.0.0)

Hi all,

We are planning to bump the VA-API major version from 0.40.0 to 1.0.0. In the new version, we will
* fix errors in API/data structure definition, e.g. https://github.com/01org/libva/issues/32
* add new features, e.g. https://github.com/01org/libva/pull/69,
* deprecate some useless API/data structures, e.g. libva-tpi, libva-egl.
* provide other improvement, e.g. use portable type to define data structure.

I have created https://github.com/01org/libva/tree/v2.0-branch for the new version bumping. You are welcome if you have any comment / suggestion or patch to improve the api

Thanks
Haihao