Add elastic band path smoother simulation

[AtsushiSakai]

Ref:
http://www8.cs.umu.se/research/ifor/dl/Control/elastic%20bands.pdf

[mukundbala]

Is this still open :)?

[Zireael07]

Yes it is, you can see the label at the top says open

[AtsushiSakai]

PR is welcome

[Aglargil]

@AtsushiSakai I am happy to add the elastic bands algorithm to the project. I noticed that it requires a distance map, and snowy can generate distance maps. Do you think it would be better to use this library, or should we implement our own method for generating distance maps?

[AtsushiSakai]

Thank you for proposal. I prefer adding own method to generate a map or generated map data file is added in this repo.
New dependency should be avoided.