Added line tracing support [clean]

[Roundaround]

Line tracing support has been added. The majority of the changes take place in the plotHover function, and revolve around a secondary tooltip calculation should the cursor not be on a data point. I've added a new options item: an object called 'lines' that has members 'track' (bool, default false) which determines if the lines between points are tracked, and 'threshold' (number, default 0.05) which determines at what distance from the line the algorithm determines the cursor is hovering over it.

Note that I did not rebuild with grunt - I only edited the source file.

Secondly, this is a re-make of the original pull request #84, with a modified target branch.

[krzysu]

Hi Evan,
if you want to be a longer time contributor I can add you to the project. This is welcomed as I don't have time to maintain this plugin regularly and I'm also not using it very often. Recently I'm just merging pull requests and taking care of code quality and documentation. Would you be interested in developing this plugin more here or do you want to keep your separate version?
Best
Kris

[Roundaround]

Hey krzysu, nice to hear from you. I'm fine with working on this version here, especially since Flot's plugin page points here already. If I have write access it really doesn't matter to me!

• Evan

[krzysu]

So welcome on board, if you need any help you can always ask.