New cpp folder structure

Signed-off-by: Alexander Borsuk <me@alex.bio>

libs/geometry/smoothing.hpp

@@ -0,0 +1,20 @@
+#pragma once
+
+#include "geometry/point2d.hpp"
+
+#include <vector>
+
+namespace m2
+{
+using GuidePointsForSmooth = std::vector<std::pair<m2::PointD, m2::PointD>>;
+
+// https://en.wikipedia.org/wiki/Centripetal_Catmull–Rom_spline
+double constexpr kUniformAplha = 0.0;
+double constexpr kCentripetalAlpha = 0.5;
+double constexpr kChordalAlpha = 1.0;
+
+void SmoothPaths(GuidePointsForSmooth const & guidePoints,
+                 size_t newPointsPerSegmentCount, double smoothAlpha,
+                 std::vector<std::vector<m2::PointD>> & paths);
+}  // namespace m2
+