data_grid() no longer fails with modern tidyr (#58).
New mape() and rsae() model quality statistics (@paulponcet, #33).
rsquare() use more robust calculation 1 - SS_res / SS_tot rather than SS_reg / SS_tot (#37).
typical() gains ordered and integer methods (@jrnold, #44), and ... argument (@jrnold, #42).
Added a NEWS.md file to track changes to the package.
Fixed R CMD CHECK note
Updated usage of reduce() for upcoming purrr release
More general permute() function
Add mse() function to calculate mean squared error. Written by @bensoltoff, pull request #57