Add new vignette to describe "lines" issue

[jeffreyhanson]

It would be useful to add a vignette that describes the lines issue in detail (#268, #205) , provides examples, and also provides recommendations on how to resolve the issue (e.g., using spatial penalties/constraints or getting better/more cost or feature data).

[jflowernet]

This would be good to have. It could also go in the FAQ I keep promising to do since it doesn't seem like it needs a whole vignette to itself. I think there is another issue about the FAQ. I can post a list of Q's that we and others can add to and I can get cracking on a vignette

[jeffreyhanson]

Yeah that's a good point - thanks @jflowernet! @ricschuster, you originally suggested a vignette for the lines issue - where do you think would be the best place to put this info (e.g., in its own vignette or an FAQ?)?