Added support for tiled processing for rasters too large to fit in memory
Added vignette: Parallel and Distributed Processing with 'rgeomorphon'
Build with -DARMA_USE_CURRENT for Armadillo 15+
Add positive, negative, and ternary arguments and output types (for #3)
Add support for 4-, 5-, and 6-form classifications via forms argument
Add forms_matrix_* methods for classifying positive and negative output using arbitrary forms matrices (lookup tables)
forms_matrix_get() to obtain forms matrices hard coded in the algorithm
forms_matrix() to create a new object of class forms_matrix (basically a factor matrix)
forms_matrix_apply() to classify positive and negative outputs using a forms_matrix
Add new Salton Sea bathymetry dataset; see ?salton