lm_data_prep: Prepare data for a linear SRA fit
In bstaton1/FitSR: Functions to Fit and Summarize SRA Models

Takes the output of the SimFit functions to prepare for fitting a linear regression model

1	lm_data_prep(params, obs)

`params`	a list object created by `SimFit::init_sim()` or `kusko_data_prep()$params`. Contains the driving parameters and dimensional variables.
`obs`	a list object created by the functions that generate observations in the `SimFit` package or the `kusko_data_prep()$obs` function.