Track recorded stats shows sensor data from trackpoints table.

Heart rate: maximum and average.
Cadence: maximum and average.
Power: average.
Fixes #525 and #502.

src/main/java/de/dennisguse/opentracks/stats/SensorStatistics.java

@@ -0,0 +1,49 @@
+package de.dennisguse.opentracks.stats;
+
+public class SensorStatistics {
+    private Float maxHr;
+    private Float avgHr;
+    private Float maxCadence;
+    private Float avgCadence;
+    private Float avgPower;
+
+    public SensorStatistics(Float maxHr, Float avgHr, Float maxCadence, Float avgCadence, Float avgPower) {
+        this.maxHr = maxHr;
+        this.avgHr = avgHr;
+        this.maxCadence = maxCadence;
+        this.avgCadence = avgCadence;
+        this.avgPower = avgPower;
+    }
+
+    public boolean hasHeartRate() {
+        return maxHr != null;
+    }
+
+    public float getMaxHeartRate() {
+        return maxHr;
+    }
+
+    public float getAvgHeartRate() {
+        return avgHr;
+    }
+
+    public boolean hasCadence() {
+        return maxCadence != null;
+    }
+
+    public float getMaxCadence() {
+        return maxCadence;
+    }
+
+    public float getAvgCadence() {
+        return avgCadence;
+    }
+
+    public boolean hasPower() {
+        return avgPower != null;
+    }
+
+    public float getAvgPower() {
+        return avgPower;
+    }
+}