RFkick bug with MTS integrator

Working on #773 (closed) I have found that there is an error produced by a wrongly implemented unit change. So up, ParallelCyclotronTracker works internally in ns, therefore, several unit changes are necessary throughout the code.

ParallelCyclotronTracker::RFkick method has as input variables t and dt in ns, as they are subsequently transformed to s in RFCavity::getMomentaKick. However, ParallelCyclotronTracker::push used with MTS integrator calculates dt1 in s, and is not changed to ns before calling RFkick, so the results are not corrected.

This error affects the RingCyclotronMTS regression tests (regression-tests#116 (closed)).