[mythtv] port of denoise3d to MythTV

[Andrew Mahone]

My port of mplayer's denoise3d filter to MythTV is done, and works great, 
although it uses a fair amount of CPU.  As I added a directory, it was easier 
to just tar everything added or changed.  The bzipped tarball is at:
http://chshrcat.homelinux.net/~chshrcat/public/mythtv-denoise3d.tar.bz2

It works with my previous patch, the options accepted are the same as for the 
mplayer vesion of the filter, accepting an option string of <l>:<c>:<t>, with 
float value for the luma, chroma, and temporal filter strengths.  If the 
options patch is not used, or no options are passed, the default 4:3:6 is 
used.  Higher settings will cause more blurring and ghosting, the defaults 
generally do a good job of reducing noise without introducing too many 
visible artefacts.

I could use a little help optimizing, this is the first I've worked in C in a 
while, and I've never dealt with SIMD...  comments from anyone who'd care to 
take a look are welcome.