deprecated check.variogram() to plot.slmfit() generic.
deprecated get.predinfo() to print.predict.slmfit() generic.
deprecated get.predplot() for plot.predict.slmfit() generic.
updated the print() generic for predict.slmfit classes.
added the stratafit(), predict.stratafit(), and related summary() and print() generics to easily perform FPBK for different strata, allowing each stratum to have different fixed effects and different covariance parameters for each stratum.
added functionality for sp and sf point geometry objects to be used as a data argument in slmfit().
added variogram function sv() to allow for more options in the empirical variogram.
added normalized residuals as an option to the residuals.slmfit() generic.
added fitted value extraction via the fitted.slmfit() generic.
removed unnecessary dependencies on matrixcalc and mvtnorm packages.
added error message for collinear predictors.
added print() generics for predict.slmfit() and slmfit().
changed UTM to TM in package functions and documentation.
Fixed an issue with using a tibble object instead of a data.frame object.
Updated error message for collinear predictors.
Changed a warning about converting characters to factors to a message.
Removed unnecessary package dependencies with sp, matrixcalc and mvtnorm and moved tibble from Imports to Suggests.