Set gain buttons to 0.00dB directly

[http://openid.aol.com/adiknoth]

Hi.

It's a common feature to set a gain value to 0.00dB directly. Ardour uses Shift+Leftclick for this.

I suggest lv2fil follows this convention, even if this means changing the modifier key for "fine-tuning" from shift to something else. (ctrl?)

[http://nedko.arnaudov.name/]

adi said on IRC: Ardour (default) keybindings are: Shift+Leftclick --> 0dB, ctrl+Leftclik --> -inf (not needed for lv2fil), ctrl+left-hold-and-adjust: fine-tune