Improve contrast in TailSpin component

[frinyvonnick]

[frinyvonnick]

@fabienjuif it seems to work accordingly to this test. But on dark colors like black contrast is a bit light.

[fabienjuif]

We should detect if the retrieve background color is more light than dark, and then apply the appropriate color transformation from this.

[frinyvonnick]

I suggested to use getBrightness from tinycolor