added support for XML reading/writing

new serialization interfaces
new helper methods
new wifi models

sensors/activity/Activity.h

@@ -0,0 +1,20 @@
+#ifndef ACTIVITY_H
+#define ACTIVITY_H
+
+enum class Activity {
+
+	STANDING,
+
+	WALKING,
+
+	WALKING_UP,
+
+	WALKING_DOWN,
+
+	ELEVATOR_UP,
+
+	ELEVATOR_DOWN,
+
+};
+
+#endif // ACTIVITY_H