some changes and fixes

[mati1210]

• fix directory creating! Fixes #16, hopefully

and

• makes ImageFilterer executable! this doesn't do anything on windows, but elsewhere it makes so you can just do

  ./ImageFilterer.py

  instead of

  python ./ImageFilterer.py

[yruen]

I'm so dumb, I kept referencing the alpha directory instead of the local variable for the for loop wow.

[mati1210]

dw That happens sometimes