Issue with odin::odin_package() when package installed in the standard place

[JDChallenger]

I noticed that, after installing the package following the instructions on github (devtools::install_github("mrc-ide/deterministic-malaria-model")), I was not able to compile changes to file 'odin_model_TBV.R'. The function 'odin::odin_package()' expects a path of the form 'inst/odin', which is not generated when the package is installed like this (on my Windows machine). Downloading the code and installing locally works fine