Updated broken references (requirements.txt) + added Chunking/Patching

[IgorAherne]

process images in chunks/patches.

This can be controlled via comandline arguments

Launch via python ./test.py --chunk_size 512 or --chunk_size 256 etc

arguments and their default values (see test.py):

--test_dir = ./ShadowDataset/test where the input images are
--input_dir = ./input/
--output_dir = ./output/
--chunk_size = 512 size of sliding window, to split the work into smaller pieces, for performance. Careful, might create seams
--overlap = 64 overlap among the windows, to hide possible seams

to install requirements.txt:
python -m pip install --upgrade pip
pip install --upgrade-strategy only-if-needed -r requirements.txt