[BUG FIX] dti_1 inversed twice in exact_cubic

include/spline/exact_cubic.h

@@ -97,7 +97,7 @@ struct exact_cubic : public curve_abc<Time, Numeric, Dim, Safe, Point>
 			if( i+2 < size)
 			{
 				In it2(next); ++ it2;
-				num_t const dTi_1(1/((*it2).first - (*next).first));
+				num_t const dTi_1((*it2).first - (*next).first);
 				num_t const dTi_1sqr(dTi_1 * dTi_1);
 				// this can be optimized but let's focus on clarity as long as not needed
 				h1(i+1, i)   =  2 / dTi;

include/spline/optimization/OptimizeSpline.h

@@ -103,7 +103,7 @@ inline void SplineOptimizer<Time, Numeric, Dim, Safe, Point>::ComputeHMatrices(I
 		if( i+2 < size)
 		{
 			In it2(next); ++ it2;
-			num_t const dTi_1(1/((*it2).first - (*next).first));
+			num_t const dTi_1((*it2).first - (*next).first);
 			num_t const dTi_1sqr(dTi_1 * dTi_1);
 			// this can be optimized but let's focus on clarity as long as not needed
 			h1(i+1, i)   =  2 / dTi;