message: Adjust colouring for pipeline flow chart, improve contrast. Closes
  * On the light theme we use a less dark background colour improving contrast
  with the text.
  * On the dark theme the background is still super dark, but we dim the outline
  colour which provides an indication of disabled stages
diff: @@ -194,14 +194,14 @@ void PipelineFlowChart::paintEvent(QPaintEvent *e)
  const qreal arrowY = totalRect.y() + totalRect.height() / 2;
  - QColor base = palette().color(QPalette::Base);
  - QColor baseText = palette().color(QPalette::Text);
  - QColor inactiveWin = palette().color(QPalette::Inactive, QPalette::Dark);
  - QColor inactiveWinText = palette().color(QPalette::Inactive, QPalette::WindowText);
  + QColor enabledBase = palette().color(QPalette::Base);
  + QColor enabledText = palette().color(QPalette::Text);
  + QColor disabledBase = palette().color(QPalette::Disabled, QPalette::Base);
  + QColor disabledText = palette().color(QPalette::Disabled, QPalette::Text);
  QColor tooltip = palette().color(QPalette::ToolTipBase);
  QColor tooltipText = palette().color(QPalette::ToolTipText);
  - QPen pen(baseText);
  + QPen pen(enabledText);
  QPen selectedPen(Qt::red);
  int num = numGaps();
  @@ -213,7 +213,7 @@ void PipelineFlowChart::paintEvent(QPaintEvent *e)
  float right = totalRect.x() + (i + 1) * (box0Rect.width() + boxMargin());
  float left = right - boxMargin();
  - p.setBrush(baseText);
  + p.setBrush(enabledText);
  drawArrow(p, pen, ArrowHeadSize, arrowY, left, right);
  }
  @@ -222,14 +222,14 @@ void PipelineFlowChart::paintEvent(QPaintEvent *e)
  {
  QRectF boxrect = boxRect(i);
  - QBrush backBrush(base);
  - QPen textPen(baseText);
  - QPen outlinePen = pen;
  + QBrush backBrush(enabledBase);
  + QPen textPen(enabledText);
  + QPen outlinePen(enabledText);
  if(!stageEnabled(i))
  {
  - backBrush.setColor(inactiveWin);
  - textPen.setColor(inactiveWinText);
  + backBrush.setColor(disabledBase);
  + outlinePen.setColor(disabledText);
  }
  if(i == m_HoverStage)
  