Simulation bugs + period

Corrected a bug where the info in sim was corrupted by PMsim. Now PMsim
is a shallow copy of sim (deriving from matlab.mixin.Copyable class).

Added a simple code to calculate the gait's period.
Added TestSim (a copy of AlexSim), to stop bugging Alex with my tests :)
Small bug

Now that sim.Period includes the number of steps for a complete cycle
and the step time, I used sim.Period(1) instead of sim.Period in
Poincare.m

NOTE: The period calculated is for the last step only. If the gait is
multi-period, a new simulation should be ran to get the IC at each step
and the period of each step in a full cycle.
Caught a bug for the EndCond = 1 sim type

When calculating the poincare map of higher periods it would keep
walking because Steps2Slope kept getting updated after each step.
Also "merged" Test.m into TestSim.m
Merge changes of master into Genetic Algorithm branch

Merge wouldn't work... will have to commit