[Push] GUPnP-DLNA API update

- Update the call to the gupnp_dlna_profile_guesser_guess_profile_sync(...)
to match a change in its signature.
- Bump GUPnP-DLNA Library required version to 0.9.4.

Signed-off-by: Christophe Guiraud <christophe.guiraud@intel.com>
[Samples] Added slidepush.py

Slidepush is a sample application that allows users to display the
contents of a presentation on a DMR.

Signed-off-by: Mark Ryan <mark.d.ryan@intel.com>
[SlidePush] Only call stop if renderer is playing.

Previously, slidepush always called stop before pushing an image to
a DMR.  However, this is only necessary if the DMR is currently playing.
SlidePush now checks the DMR's PlayStatus to ensure it is Playing before
calling Stop.

Signed-off-by: Mark Ryan <mark.d.ryan@intel.com>
[SlidePush] SlidePush now supports PDF files.

Signed-off-by: Mark Ryan <mark.d.ryan@intel.com>