Fixed several small (stupid) issues with the inpaint node:
* on pixel order building, some ranges got wrong and origin was considered
several times.
* the convolution kernel didn't consider all pixels (+1,0),(-1,0),(0,1) and (0-1)
were omited, leading to suboptimal results (sometimes even black areas)
* alpha channel is now only affected an areas considered by inpaint.
That's only important, if you choose low iteration counts.