Fixing build on windows.
Merge branch 'master' into SlideFactory
Fixing plib.h for cross platform. (avoid configuration step)
Adding routine to add a slide to the presentation.
Renaming PresentationXml and Slide to PresentationPart and SlidePart.
Adding SlidePartBuilder.
Adding functions to generate basic slides: Title slide and bullet list slide.
Renaming content slide to bullet list.