ILP vignette

[edwardsmarc]

Add a vignette on ILP. Targeted at the average user who understands the SCP concepts but not the mathematical underpinnings. ILP 101 if you will.

I think a bit of background on this will help the intermediate to advanced user understand best practices and trade-off's between different approaches (e.g. those discussed in calibrating_trade-offs_tutorial.Rmd).

[jeffreyhanson]

Thanks again for raising this @edwardsmarc!