World tile grid theme cruft remover that can be used with any other theme

Removes:

theme_enhance_wtg(move_legend = FALSE)

Arguments

move_legend	if `TRUE` will move the legend to c(0.2, 0.2) and make it horizontal as well as give it a width of 2 lines. You should add a call to `guides(fill = guide_colourbar(title.position="top"))` and, perhaps, center the legend title. Default is `FALSE` for backwards compatibility.