Watermark loader

A filter loader providing watermark capabilities, which means, that in fact its a paste-filter, with some other options.

    watermark:
        image: Resources/data/watermark.png # the watermark itself
        size: 0.5 # Size of the watermark relative to the origin images size (also "50%), may be null, default null
        position: center # one of topleft,top,topright,left,center,right,bottomleft,bottom,bottomright  default center

If `size` it is missing, it will downscale the image if needed, or it will keep the size as it is. This filter loader will keep the watermarks image ratio always as it is.