iw3 output resize suggest

[OHLIA]

I want to use 1080P video to outpu FULL SBS video, it output size is 3840x1080，can iw3 implement the resize options, then i can resize it to 3840x2160 half SBS video?
Why i do that? Because 4K video run iw3 to output half sbs videos will use much times, i found use 1080P to make full sbs videos，then use others software resize to 3840x2160, the quality is enough. If IW3 can implement the resize funtion, it will reduce times.

[nagadomi]

see #227