Fix byte order for PSPacked422 users

Byte order was changed in 9595a78e8a272cc15ada4d456bc547ffcac3b73e
Fix typo in conversion technique name (there is no UYUV, only UYVY)
Make PSPacked422_Reverse sample in texel center
Initial implementation of a v4l2 capture plugin
v4l2 plugin properties
added ability to choose device, pixel format, resolution and
frame rate