Fix Histogram SEGV and Speed

.. SEGV caused by referencing data->isChecked when
   not in range mode

.. Speed plotting broken because line setting the
   array length in setData was accidentally deleted

src/HistogramWindow.cpp

@@ -366,7 +366,7 @@ HistogramWindow::compareChanged()
         powerHist->setSumY(showSumY->currentIndex()== 0 ? true : false);
 
         // set data and create empty curves
-        if (data->isChecked()) {
+        if (!rangemode || data->isChecked()) {
             // using the bests (ride file cache)
             powerHist->setDataFromCompare();
         } else {

src/PowerHist.cpp

@@ -374,6 +374,7 @@ PowerHist::recalcCompare()
         } else if (series == RideFile::kph) {
 
             array = &cid.kphArray;
+            arrayLength = cid.kphArray.size();
 
         } else if (series == RideFile::cad) {
             array = &cid.cadArray;