massive refactoring to switch from camelCase to snake_case: historically, Libervia (SàT before) was using camelCase as allowed by PEP8 when using a pre-PEP8 code, to use the same coding style as in Twisted. However, snake_case is more readable and it's better to follow PEP8 best practices, so it has been decided to move on full snake_case. Because Libervia has a huge codebase, this ended with a ugly mix of camelCase and snake_case. To fix that, this patch does a big refactoring by renaming every function and method (including bridge) that are not coming from Twisted or Wokkel, to use fully snake_case. This is a massive change, and may result in some bugs.