first implementation of legend

src/i0mmonplot.cpp

@@ -68,6 +68,7 @@ void I0MMonPlot::setSources(const QString &x, const QString &y, const QMap<int,
     m_lambdas = lambdamap;
     m_time_mode = (x == "time");
     m_reset_scales();
+    int la = 1;
     foreach(double l, lambdamap.values()) {
         QString cuna = QString("lambda %1").arg(l);
         QuPlotCurve *crv = curve(cuna);
@@ -77,6 +78,7 @@ void I0MMonPlot::setSources(const QString &x, const QString &y, const QMap<int,
             QPen p = crv->pen();
             p.setWidthF(2.5);
             crv->setPen(p);
+            crv->setTitle(QString("λ %1").arg(la++));
         }
         m_curvesymap[cuna] = m_symstyles[m_curvesymap.size() % m_symstyles.size()];
     }