Fix Trajectory timestamp generation

The Trajectory constructor generates timestamps using GenerateTimestamps, if those aren't provided by the caller. However, due to rounding issues, the returned timestamps sometimes lacked one timestamp.

Problem occurred while implementing Implement 'PointAt'-skill (sw/armarx/skills/control!53 - merged)

source/RobotAPI/libraries/core/Trajectory.cpp

@@ -1668,7 +1668,7 @@ namespace armarx
         }
 
         Ice::DoubleSeq result;
-        size_t size = int((endTime - startTime) / stepSize) + 1;
+        size_t size = std::round((endTime - startTime) / stepSize) + 1;
         stepSize = (endTime - startTime) / (size - 1);
         result.reserve(size);