- `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.