Enables style sheets for knob line colors for all knob types

[michaelgregorius]

The fix works as follows: until now the method Knob::drawKnob has used
hard coded palette colors to draw the knob lines for the different knob
types. These palette colors are now assigned to the line color property
in Knob::initUi. The method Knob::drawKnob in turn now uses the line
color property for almost all knob types. This means that all knobs
lines will be painted in the same color as before unless that property
is overridden by the stylesheet.

Also removes an unnecessary typedef from QWidget to trackSettingsWidget
in Track.h.

This commit fixes the problem described in HDDigitizerMusic#3.

[tresf]

FYI, Travis error was a stalled Mac build. Re-started to ensure it passes (which it should). 👍

[tresf]

Very interesting.... so lineColor was already part of the API but wasn't used for this particular draw function? Elegant.

[michaelgregorius]

@tresf Yes, the property lineColor was neither used in the style sheet nor in the code.

[michaelgregorius]

@tresf I have just rebased against the current master which does not have the enum knobGreen_17 anymore. So the poor build server will have to go through all this again anyway. 😄

[IvanMaldonado]

Where in the .css file can I change the color? this didn't fix it for me, the color is still linked by qproperty-windowText.

[michaelgregorius]

@IvanMaldonado You should be able to change the line color using the lineColor property. For example if you want to switch the knob line color for the TrackViews you can use the following CSS:

TrackView Knob {
    qproperty-lineColor: rgb(255, 0, 0);
}

[IvanMaldonado]

@michaelgregorius Thank you! I didn't know you had to do that, it works fine for me 👍

Edit: What about the bigger knobs?

[Umcaruje]

@IvanMaldonado Just put Knob rather than TrackView Knob in the CSS

[IvanMaldonado]

@Umcaruje Thank you 👍

[michaelgregorius]

@IvanMaldonado Sorry, I was not messaged with regards to your edit but it looks like your question got answered.