Added a Trajectory structure to improve the user utilisation

[thibaultbarbie]

I think it is important for the user to have many different information when computing a trajectory. For example it could be useful to know the length (in cartesian space) of the trajectory, or the cost of a trajectory, or the smoothness.

To allow it we need to have a Trajectory structure that can give all of these information . I just created the structure and put the Vec<Vec> behing the "waypoints" attribute but if you think this is a good idea we can then extend it to something with more information.

By the way, I would be interested to create a crate for motion planning in Rust by first starting to modify your crate and then extending it to allow multiple motion planners, would you be interested ?

[OTL]

Hi.

Do you know below crate?

https://github.com/samueltardieu/pathfinding

When I implemented this crate, I thought that I should add rrt to the pathfinding crate at first.
But Rust prefer small crate then larger one. So I decided to crate small rrt crate.

Could you tell me your plan?

[thibaultbarbie]

Yes I know this crate, but I think it will be better to have a specific crate for robotic path planning.

I see. I understand that having small crates is more "rusty". Well, in this case we could have one big crate named "path-planning-rs" or something like this and, inside this crate we could call your crate.

However, I still think that your algorithm should output a trajectory structure instead of the raw trajectory inside a Vec<Vec> because if one day you want to expand it it will be far easier.