Add egg-fetcher demo

static/egg-fetcher/assets/sprites/Readme.txt

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+Hey,
+Thanks for choosing my pack!
+
+If you missed it, the license of this pack is Creative Commons 0
+(aka Public Domain). That means that you can use it in personal,
+educational, commercial and other projects.
+
+The link to my profile is good, but fully optional. If you want
+to put it, link to https://comigo.itch.io/, and call me CoMiGo.
+
+You can also donate $3 USD or more and get the source project of it.
+It can be opened with Gravit Designer, a freemium app that works
+online and on desktop. Almost the whole asset pack was made with
+its free version, so you will be able to create new sprites from
+that project easier.
+
+It will also help me create new asset packs, which is good <3
+The source file can be purchased at
+https://comigo.itch.io/farm-puzzle-animals
+
+Happy coding!
+~ CoMiGo