Further downsize the NAMESPACE

[thomas-muench]

Currently, the grfxtools NAMESPACE has been reduced drastically already in the dev version by throwing out unnecessary package exports, but still the maptools package is needed to be imported into the NAMESPACE, so that the wrld_simpl data can be loaded within ggpolar() using utils::data(). This results still in a quite large NAMESPACE for grfxtools which seems inappropriate for such a (still) small package. Consider adding the wrld_simpl object from maptools as internal data to grfxtools to entirely remove the dependency on maptools. This requires checking the license terms!

[thomas-muench]

Closed by 6e02cd3.