0.7
  adapted to gem 0.91 by iohannes + rendering problems
0.6
  added colorspace message, now we can choose what to decode the YV12 into:
  YUV, RGBA/BGRA, or RGB/BGR
  uses color conversions from GemPixUtil.cpp
0.5
  fixed help patches for pd 0.37
0.4
  fixed pdp-0.12 compatibility on my own this time
0.3
  fixed pdp-0.11 compatibility with advice from Thomas Wurzer
0.2
  added pdp2gem based on a skeleton of pix_film
  spare a refresh in gem2pdp (faster)
0.1
  first implementation : includes gem2pdp
