- added .qt and .pls file extensions.

* modules/gui/macosx/intf.m:
  - increased the number of lines the messages dialog can hold to 400.

* added fourcc '3iv1' to .avi and .mov
  - this is 3ivx D3.5 video.
  - we cannot read them at however and probably never will. I added them
    for completeness.

* added fourcc '3iv2' to .avi and ffmpeg
  - this is 3ivx D4 video
  - it is mpeg 4 compliant and ffmpeg decodes it, via MPEG4.

* added fourcc '3ivd' to .avi, .mov and ffmpeg.
  - this is video which was divx doctored by the 3ivx doctor program.
  - it is normal DIV3 video and ffmpeg decodes it via MPEG4 v3.

* added fourcc '3vid' to .avi, .mov and ffmpeg.
  - this is incorrect encoded DIV3. it is an endianness issue by the encoder.
  - ffmpeg can decode it however, so it is mapped to MPEG4 v3.