Fix precision error in ros clock sleep (#528)

ros clock used AlicaTime::inSeconds() to convert
the duration of the sleep to seconds. However, this
works out to 0 for any time interval < 1 sec. Since
the sleep time is 33 ms in step engine, this can
cause problems. Futher, this rounding behaviour
is not intuitive for users of the clock in general

supplementary/alica_ros1/alica_ros_proxy/src/clock/AlicaROSClock.cpp

@@ -1,3 +1,4 @@
+#include "engine/AlicaClock.h"
 #include "ros/time.h"
 #include <clock/AlicaROSClock.h>
 
@@ -18,7 +19,7 @@ alica::AlicaTime AlicaROSClock::now() const
 
 void AlicaROSClock::sleep(const alica::AlicaTime& time) const
 {
-    ros::Duration(time.inSeconds()).sleep();
+    ros::Duration((double) time.inNanoseconds() / alica::AlicaTime::seconds(1).inNanoseconds()).sleep();
 }
 
 } // namespace alicaRosProxy