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
Disable channel icon scan when icon path is empty

XBMC checks the icon path and terminates the scan early if no path is set. This commit causes the setting to respect that.
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