huge commit

- worked on about everything
- grid walker using plugable modules
- wifi models
- new distributions
- worked on geometric data-structures
- added typesafe timestamps
- worked on grid-building
- added sensor-classes
- added sensor analysis (step-detection, turn-detection)
- offline data reader
- many test-cases

sensors/imu/AccelerometerData.h

@@ -0,0 +1,23 @@
+#ifndef ACCELEROMETERDATA_H
+#define ACCELEROMETERDATA_H
+
+#include <cmath>
+
+/** data received from an accelerometer sensor */
+struct AccelerometerData {
+
+	float x;
+	float y;
+	float z;
+
+	AccelerometerData() : x(0), y(0), z(0) {;}
+
+	AccelerometerData(const float x, const float y, const float z) : x(x), y(y), z(z) {;}
+
+	float magnitude() const {
+		return std::sqrt( x*x + y*y + z*z );
+	}
+
+};
+
+#endif // ACCELEROMETERDATA_H