Android: support subs through an INTENT

VLC for Android currently supports streaming from DLNA/UPnP servers from within the app itself or with help of other apps (like BubbleUPNP), it also supports subtitles from such sources provided they are embedded in the file being streamed itself. Unfortunately VLC does not support subtitles stored on the server in a different file (SRT). Even though this feature is not part of DLNA specs, most server software implements it in some way. For example Kodi (https://kodi.tv/), and MiniDLNA. Support for playing those from the app itself can be tricky, and probably requires changes to core to accommodate the different standards (Currently as noted here http://trac.kodi.tv/ticket/15142 there are 2 ways subtitles are served), however it is a very important feature. Additionally, this feature https://trac.videolan.org/vlc/ticket/14705, could possibly allow VLC to at least play subtitles over network when DLNA is handled in an external app (like BubbleUpnp ), and the media is just handed over to VLC as an intent. This would put VLC at parity to other Android players such as MXPlayer.