updated nls_table and lm_table to work with tibble 3.0.0;

new function: rm_empty_cols; this function is used internally to better handle optional variables;

added a new dependency, forcats;

new function: ident_model_full; this function runs the complete identity model test;

fixed a bug where lm_table and nls_table would sometimes change the order of coefficients;

graybill_f now accepts vectors as input;

average_tree_curve now has a color argument, that allows variables to be mapped as colors;

average_tree_curve now plots a mirrored plot, as to resemble a tree (mirror argument) and has an argument to remove the equation from the plot;

rmse_perc and bias_perc now have a na.rm argument (which is TRUE by default);

updated tree_summarise to sum volume with and without bark using 2 new arguments;

fixed vol_summarise handlying of optional variables;

new function: class_center;

diameter_class and bdq_meyer can now handle all values of class intervals correctly.

Graybill_F is now graybill_f;

removed unnecessary imports;

updated description;

converted all exemple data to tibbles;

removed head command from examples, since itâ€™s not necessary anymore;

fixed some typos;

added a gray_scale argument to est_clutter function;

fixed a bug where if a dataframe cointaned NA, resid_plot would fail;

vol_summarise now outputs ungrouped data;

fixed vol_summarise name for average form factor value;

fixed the example of lm_table;

fixed the example of strs; number of plots needed to be sampled was wrong;

changed exfm19 to a data by tree;

added 6 vignettes in portuguese;

added 6 vignettes in english;

tree_summarise is now improved, and keeps all variables from data;

strs can now handle special characters;

added a new example data, with revenue values for a eucalyptus forest;

added a new function, npv_irr, for net present value, irr calculation and sensibility evaluation;

fixed a bug in huberwob, which made a wrong call to df;

fixed bugs in various functions, with a call for is.na with a 2 length vector.

- release