Pocket Extras + Other Stuff

New Stuff:

• Pocket Extras
• GB Palettes
• Library Images

What's Changed

• Added manual help text by @hallem in #250
• Added ability to download the GameBoy Palettes & Pocket Library Images by @hallem in #251
• Added indicators for the sub menus by @hallem in #253
• Pocket Extras Support & Other Stuff by @hallem in #255
• version bump by @mattpannella in #256
• include pocket_extras.json in release by @mattpannella in #257
• Fixed copy/paste error by @hallem in #258

Full Changelog: 3.3.1...3.4.0