Modify code to store solved trajectories as an option

[broncio123]

This seems a very useful feature for user-experience, to visualize how trajectories seat in phase-space alongside manifolds.

By default, they shouldn't be stored, as the main objective is to compute the LD functions. As these result in increased storage. However, this can be kept as an option for users.

In the same line of thinking. A useful function to create would be to extract/solve trajectories for initial conditions extracted (using gradient approach) from manifolds.

[vkrajnak]

As discussed, it may be worth having a separate function to generate a lower dimensional set of trajectories (such as initial conditions on/close to invariant manifolds) that would allow defining a return map.