Make dodge_width an adjustable param

[Colin Conwell]

Thanks for this excellent function! just a minor feature request. Can you allow dodge width (for position_dodge) to be a settable param? I forked and tested on my end, so something like the following should work:

geom_pirate <- function(mapping = NULL, data = NULL,
                        ...,
                        points = TRUE,
                        bars = TRUE,
                        lines = TRUE,
                        cis = TRUE,
                        violins = TRUE,
                        points_params = list(shape = 1, size = 1),
                        bars_params = list(alpha = 0.3, width = 0.9),
                        lines_params = list(size = 0.5, width = 0.9),
                        cis_params = list(fill = "white", size = 0.5,
                                          alpha = 0.5, width = 0.8),
                        violins_params = list(fill = "white", size = 0.5,
                                              alpha = 0, width = 0.7),
                        dodge_width = 0.9, #this (along with changing it in the subfunctions) should do it.
                        jitter_width = 0.2,
                        na.rm = FALSE,
                        show.legend = FALSE,
                        inherit.aes = TRUE)