libvpx

Merge changes Ide5eefad,I28026b86,Ie9a6fac0,Ia8a20c67,I8c7f5b97,I33ca9cdd,I438cbf49

* changes:
  vp8_regular_quantize_b_sse2: remove dead init
  vp8cx_pick_filter_level*: remove dead inits
  vp8_decode_frame: remove dead increment
  rdopt: remove dead stores
  find_next_key_frame: remove dead init & store
  multiframe_quality_enhance_block: remove dead stores
  vp8_print_modes_and_motion_vectors: remove dead stores