new_location() when calling new_element(). The R2PptxLocation class is now exported. The R2PptxLocation class has slots ph_location_fn (function) and args (list) instead of the location character slot (#8).R2PptxSlideList improvements (#3)
Added + method to add R2PptxSlideList objects to R2PptxSlideList objects
Added new_slidelist() to create new slide list objects