Include request for reset-rework branch v4 PART2

[j.glisse at gmail.com]

So here are sa improvement, ib pool cleanup and semaphore cleanup.
Those are Christian patches rebased on top of its last 17 patchset
and on top of sa allocator change.

The idea is that the sa_bo struct is not free until associated fence
is signaled. Meanwhile the ib structure or the semaphore/fence structure
holding a reference to the sa_bo can be free.

I have given this patchset moderated testing (things seems ok with desktop
firefox, libreoffice, evince, + few gl app running at the same time.

I haven't tested the semaphore things or vm change yet.

Patch can also be found:
http://people.freedesktop.org/~glisse/reset3/

Cheers,
Jerome