.its support

[lucasgautheron]

• [x] adding new columns
  • [x] lena_conversation_type
  • [x] lena_conversation_number
  • [x] utterrances_count
  • [x] utterrances_length
  • [x] non_speech_length
  • [x] average_db
  • [x] peak_db
  • [x] utterances
• [ ] proper tests using truth values
• [x] documentation