gallium: add blending to pipe blit
nvc0: use blending to pipe blit
nvc0: NULL vertex buffers are allowed
nv50/ir/tgsi: handle TGSI_OPCODE_CND
nvc0: reset constant vertex attribute data after blit

To make wine's test_vshader_input happy.
nvc0: add fast-path for constant buffer upload

Saves a memcpy, and increased threshold for push method, which is
usually better because there's no subchannel switch.
nvc0: don't update vbufs that aren't being accessed
nv50: record CB slot for bound constant buffers

So we don't have to re-bind every time a transfer on a bound buffer
is performed, i.e. on all constant uploads with d3d9.
nv50/ir/tgsi: handle TGSI_OPCODE_ARR
nv50/ir/tgsi: implement TGSI_OPCODE_BREAKC
nine: Add state tracker nine for Direct3D9

Work of Joakim Sindholt (zhasha) and Christoph Bumiller (chrisbmr).
v2 Small fixies and sync with latest Mesa by David Heidelberger (okias).
v3 Build improvements by Emil Velikov (xexaxo).
v4 Modified to use directly PIPE_CAP_VIDEO_MEMORY
instead of PIPE_CAP_DEVICE_MEMORY_SIZE.
v5 Merged few small fixes by okias