Fixes for BMP file output
Fixes for BMP file output

- RGB to BGR conversion was broken
- Scanline size was incorrect when copying to temporary buffer
- Force UINT8 output for now, which is what the rest of the writer assumes
  (BMP doesn't support many channel formats in any case).


git-svn-id: c3edda122e248ef33995da003806c930f62b9468@1755 31904243-a364-42ac-a3db-9305396518ba

jeremyselan/oiio,lgritz/oiio,sambler/oiio,scott-wilson/oiio,cwilling/oiio,YangYangTL/oiio,bdeluca/oiio,bdeluca/oiio,sambler/oiio,jeremyselan/oiio,scott-wilson/oiio,mcanthony/oiio,YangYangTL/oiio,jeremyselan/oiio,micler/oiio,sambler/oiio,cwilling/oiio,YangYangTL/oiio,sambler/oiio,cwilling/oiio,micler/oiio,bdeluca/oiio,mcanthony/oiio,mcanthony/oiio,lgritz/oiio,micler/oiio,bdeluca/oiio,OpenImageIO/oiio,OpenImageIO/oiio,lgritz/oiio,scott-wilson/oiio,cwilling/oiio,OpenImageIO/oiio,scott-wilson/oiio,YangYangTL/oiio,mcanthony/oiio,micler/oiio,OpenImageIO/oiio,lgritz/oiio