[Device] Add OpenUriEx player method

- Add a new player interface method OpenUriEx, which is the same as
the existing OpenUri one, with an additional metadata parameter to pass
the URI description information in DIDL-Lite XML format.
- Documentation updated.
- Renderer Console python test application updated.
- Fix issue: https://github.com/01org/dleyna-renderer/issues/25

Signed-off-by: Christophe Guiraud <christophe.guiraud@intel.com>