libvpx

Merge changes I0e4d807f,Ia5ff575c,Ie4a1f313

* changes:
  gen_msvs_*proj.sh: strip SRC_PATH_BARE from obj names
  *.mk: pass SRC_PATH_BARE to all GEN_VCPROJ invocations
  build/msvs: fix builds in source dirs with spaces