v0.1.13

• In the div_plot() and seq_plot() internal functions, replaced if (class(input) == "im") with if (methods::is(input, "im"))
• Added methods package to Imports
• Re-added utils package to Suggests because "zzz.R" calls the packageDescription() function
• Moved spatstat.random package from Imports to Suggests because the rpoispp() function is only used for tests
• Fixed bug in perlrren() function that will now keep the predicted values even if NA
• Fixed bug in plot_perturb() function that will now project rasters using method = "bilinear" for continuous values
• Streamlined "test-perlrren.R" by removing duplicate tests for "incorrectly specified n_sim"
• Fixed bug in "test-plot_cv.R" by resetting the graphics within an error check to clear a warning between tests