Properly handle files without elevation data

src/data/graph.h

@@ -54,6 +54,7 @@ public:
 				return false;
 		return true;
 	}
+
 	bool hasTime() const
 	{
 		for (int i = 0; i < size(); i++) {

src/data/route.cpp

@@ -1,4 +1,3 @@
-#include "dem.h"
 #include "route.h"
 
 

src/data/track.cpp

@@ -1,4 +1,3 @@
-#include "dem.h"
 #include "track.h"
 
 
@@ -177,7 +176,7 @@ Graph Track::elevation() const
 		GraphSegment gs;
 
 		for (int j = 0; j < sd.size(); j++) {
-			if (seg.outliers.contains(j))
+			if (!sd.at(j).hasElevation() || seg.outliers.contains(j))
 				continue;
 			gs.append(GraphPoint(seg.distance.at(j), seg.time.at(j),
 			  sd.at(j).elevation()));