lib/player: throw when unable to create session
It's possible that we can't create a session, whenever from media-hub crashing from the begining or whatever reason. And since our code isn't particularly guarded against this case, just throw a runtime_error to signal this to the consumer.
Related: #63 (closed)
Test with qtubuntu-media!13 (merged) for the best result.
Edited by Ratchanan Srirattanamet