Added Gimp course's notes.
[gimp] Adding some materials.
Added color manipulation topic.
Copy paste from LaTeX tutorial.
Basic structure.
Starting the first exercise.
First screenshot.
Booklet sketch take one.
[gimp] Removed arrows.
Added icons for some tools.
One more image that I forgot before
Selection tools added to .tex. Poorly.
Updated .gitignore to ignore the pdf and the latexmk stuff.
Section 3.1 done, 3.2 incoming.
More Tools placeholdered
Introduction halfway done.
Fixed tool size shortcut.
Finished introduction exercise.
Actually explained some of the selection tools.
[gimp] First section done.