`rickroll.sh` version 0.12 (early-dev)

• Update the README (obviously).
• Seperate stages (get_audio, play_audio, play_video) into functions.
• Fixed caching and python/python3.
• Add grab from gimme to download. gimme now only downloads nonexistent files.
• Do not use STDOUT for download.
• Do not Save cursor, clear screen before video plays.
• Increase FPS to 28 for better Audio/Video sync.
• Update cmdline options.
• Fixed bugs.

NOTES:
there was a v0.1, but it didn't work.

Commits: https://github.com/4yman-0/rickroll.sh/commits/v0.12