Allow player to retry read in case of read errors

As discussed here: https://github.com/xbmc/xbmc/commit/5c7a19af995b4933595ee9edbee0d6ac768d643d#commitcomment-8220173
@topfs2 @FernetMenta for review
but it is the only client for PVRFile and the most important one for Kodi. you should change your priorities and focus more on actual scenarios. nobody benefits from harmonizing some API if it breaks the upper layers.