Files being searched for images are only read once

The files marked for searching image usage were being re-read for each image. This ensures that they are only read once on each run-through.

For anyone who was trying to run this program on large projects and your CPU was suddenly stuck on 100% usage: Rejoice!

P.S. I'm sorry but I also added a .gitignore file. It was missing and git was bugging me, so I added the most basic version that I could :)