Added simple script to run from directory

[ducha-aiki]

Hi,

Your model is incredible. I have written a simple script to allow people quickly run on their data without bothering with data loaders, etc and instead provide intrinsics directly in cli. like this:

python -utt predict_dir.py --indir my_input_dir --outdir my_output_dir --fx 1433 --fy 1433 --cx 720 --cy 960