PlayerCoreFactory: use const reference
CPlayerCoreConfig: add PlaysAudio() and PlaysVideo()
CPlayerCoreFactory: add GetPlayerConfig() taking a PLAYERCOREID
json-rpc: add Player.GetPlayers
jsonrpc: add "playercoreid" option to Player.Open
json-rpc: bump API version to 6.17.0
Merge pull request #5122 from Montellese/jsonrpc_player_select

JSON-RPC: add possibility to specify the player to be used