Keytap3: pre-release

Major changes:

• New substitution cipher attack (Beam Search)
• Improved key-press detection
• Improved clustering strategy
• Improved N-gram English statistics (now using 6-grams, including "Space")
• Full automation of the algorithm (no longer need to provide "hints")
• Fixed audio filtering bugs

Created a demo page that can by used to check if a keyboard is vulnerable to the attack:

https://keytap3.ggerganov.com