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.
- `parseSize` lets parse a size which can be either a int, or a string with a symbol like
`Mio`
- `getSizeMultiplier` returns a tuple of size with it's multiplier symbol
- `getHumanSize` returns a string with size and adapted multiplier.
- a new `utils` module has been added for backend and frontends generic utilities
- per_luminance method calculate the perceived luminance of a colour (is it dark or
light?). This is useful to automatically select the suitable colour in a theme.
