Small issue in repo

[tomer-grin]

Two small issues regarding this great implementation:

1. Should add here int around the index (in case the index comes out as a float.
   

   multi-band-blending/multi_band_blending.py

   Line 39 in 7dae113

   mask[:, :w1 - overlap_w / 2] = 1

2. Should add warning/assert regarding shapes of images that are supposed to be the same