Add "busydialogdelayms" advanced setting.

Provides control over the delay until busy dialog is shown when starting
video playback.
Added a boolean condition to identify the Raspberry Pi platform (System.Platform.Linux.RaspberryPi)
PVR: Resolve channel dummy in GUIWindowPVRTimerSettings

When using Backend channel number , use channel unique ID member instead channel number
PVR: Cosmetics in GUIWindowPVRTimerSettings
remove old unused renderer files
Show values of string settings with button controls
remove unload/reload of fonts when init/destroy window, as it's not needed anymore
Defer demuxer pause until buffers full
add infolabel Player.Filename
CurlFile: request UTF-8 as preferable charset
CurlFile: don't set 'keep-alive' as cURL do this internally
Some web servers can't properly handle duplicated header value.
[GUIInfoManager] Add VideoPlayer.AudioLanguage infolabel.
[DVDPlayer] Set CMediaSettings::Get().GetCurrentVideoSettings().m_AudioStream on open/set.
revert 5fd167da1ebf407dcb4afa87d1a3bd5a6d66fedb
[Win32] resolution of namespace std:: conflict for bind()
add audio and subtitle language info to video osd if available
[release] version bump to 13.0 alpha10 as we start new merge window
changed: Make network buffer more flexible/configurable
changed: Move read cache logic from DVDPlayer to CFile
fixed: Tab -> space