Add support for channel gate settings

[romainp-git]

Hi. Great work so far. I'm waiting for the feedbacks, but I know it's a tough subject. I'd like to know if it's possible to add some settings functions to the module. I explain: I'd like to set a gate on a channel and I can't with companion. Do you think it's a functionality you could work on?
Thks a lot.

[fmalcher]

Thank you for your feature request!
I'm a bit reluctant to implement gate support into the connection lib since this would make things a lot more complex. Even though the gate is "just 4 faders", each of those fader ranges (e.g. threshold between -Infinity and 6 dB) is represented as an internal numeric value between 0 and 1. We will have to find out how we can convert fader values to those internal values and back. If the conversion is linear, this is a undramatic task. However, when it comes to logarithmic dB values, it might be necessary to use a lookup table as I did for the channel and gain faders.

What makes it even more complex is that the Ui12/Ui16 models have different gate params than the Ui24R so we'd have to differentiate between the models.

[TheMrPoseidon]

@fmalcher This reminds me about the calculation of DB values. Crazy function I can say.