use `RecipesBase` instead of `Plots`

[orso82]

Plots recipes are powerful! and don't bring all the Plots baggage with them :) See here for some examples: https://github.com/ProjectTorreyPines/IMAS.jl/blob/master/src/plot.jl once you learn how to use them, there is no going back! 🍦

[bclyons12]

@orso82 In this case, I'm not defining a plot for a type. Rather, I'm allowing plotting for debugging. I did this with an optional statement:

function __init__()
    @require Plots = "91a5bcdd-55d7-5caf-9e0b-520d859cae80" include("plot.jl")
end

There's no way to accomplish this with recipes I believe.

[orso82]

I should have said that this issue was written in the context of #10 , which removes Plots.jl as direct dependency of the main Project.toml and instead adds it as a dependency to the test/Project.toml

[bclyons12]

This is completed over time.