Add Slide Show to View menu and toolbar:
- uses own slideshow implementation (same as Showfoto/Image Editor)
- implemented with preview, so can be also used as full screen preview
- left KIPI-plugin in Tools menu (should be renamed to reduce confusion)
TODO: find good keyboard shortcut to assign to Slide Show function
- all obvious ones are already used: F5 (powerpoint), F12 (kpresenter)
CCBUG: 135655
BUG: 140303, 140304