[ ngslideshow] and [ gpslideshow] – peaceful co-existence for [ slideshow ] shortcodes

When you want to display a slideshow of images there are quite a few choices for plugins. See Galleries and Slideshows. Unfortunately both nextgen-gallery and slideshow-gallery-pro both used the same shortcode to display a slideshow using the [ slideshow] shortcode. But I want to be able to use both of them in my sites. So oik provides two alternative shortcodes which support peaceful co-existence of the plugins and the ability to choose the slideshow you actually want. The shortcodes are: [ ngslideshow] – for the NextGen gallery slideshow [ gpslideshow] – for the Slideshow gallery pro slideshow