`pos` order is inconsistent for different sides

[willgearty]

No one has complained about this (yet), but it looks like the behavior of the pos argument is different for whichever side you are specifying.

For example, for the bottom axis, the scales are added from the plot outwards:

ggplot() +
    geom_point(aes(y = runif(1000, 0, 8), x = runif(1000, 0, 100))) +
    scale_x_reverse() +
    coord_geo(
        xlim = c(100, 0), ylim = c(0, 8), pos = as.list(rep("bottom", 3)),
        dat = list("stages", "epochs", "periods"),
        height = list(unit(4, "lines"), unit(4, "lines"), unit(2, "line")),
        rot = list(90, 90, 0), size = list(2.5, 2.5, 5), abbrv = FALSE
    ) +
    theme_classic()

But for the top axis, the scales are added from the outside inwards:

ggplot() +
    geom_point(aes(y = runif(1000, 0, 8), x = runif(1000, 0, 100))) +
    scale_x_reverse() +
    coord_geo(
        xlim = c(100, 0), ylim = c(0, 8), pos = as.list(rep("top", 3)),
        dat = list("stages", "epochs", "periods"),
        height = list(unit(4, "lines"), unit(4, "lines"), unit(2, "line")),
        rot = list(90, 90, 0), size = list(2.5, 2.5, 5), abbrv = FALSE
    ) +
    theme_classic()

The same is true for left (inside outwards) and right (outside inwards) scales.

[willgearty]

On the one hand, at least their relative positions to one another are the same for top/bottom and for left/right, so maybe this is fine? On the other hand, the behavior of palaeoverse::axis_geo is to always add scales outwards which seems like a good behavior to me.

It shouldn't be too hard to mimic this behavior by just reversing the order of the grobs for the left and top options in this section: https://github.com/willgearty/deeptime/blob/4bf2fdfb19d25b1218531b9add7243eb3d9c50e3/R/coord_geo.R#L232-L264