sim_data_cs: generate simulated cross-section data for testing purposes
In vh-d/SFAt: SFAt: Stochastic frontier analysis on cross-section and panel data

generate simulated cross-section data for testing purposes

1 2	sim_data_cs(N = 500, x_coeff = c(10, 6, 3), z_coeff = c(3, 1.5, 0.5), sigma_u = 2, sigma_v = 3, ineff = -1, aslist = F)

`N`	number of observations
`x_coeff`	coefficients for explanatory variables
`z_coeff`	coefficients for exogeneous varaibles
`sigma_u`	variance of the inefficiency term
`sigma_v`	variance of the random noise
`ineff`	production (-1) or cost inefficiency form (1),
`aslist`	TRUE/FALSE to return list or array