PVR: Resolve channel dummy in GUIWindowPVRTimerSettings

When using Backend channel number , use channel unique ID member instead channel number
PVR: Cosmetics in GUIWindowPVRTimerSettings
changed: Make network buffer more flexible/configurable
changed: Move read cache logic from DVDPlayer to CFile
fixed: Tab -> space
CFile: fix null pointer dereference in Stat() and Write()
[vfs] CFile: add null pointers checks
videodb: add SetDetailsForMovieSet
jsonrpc: add VideoLibrary.SetMovieSetDetails
[rbp/omxplayer] Fix crash on stopping mp3 playback with amplification

There is a race condition where we can try to adjust volume after deinitialation
when amplification is enabled, causing a seg fault.
Merge pull request #3561 from popcornmix/amp_deinit_crash

[rbp/omxplayer] Fix crash on stopping mp3 playback with amplification
AESinkALSA: Use the sink in blocking fashion
adds left, top, right, bottom, centerx, centery to the list of xml nodes that can take constants
support positioning dialogs via <left> and <top>
ensure library:// folder URLs have slash at end
Merge pull request #3534 from Karlson2k/cfile_fix_01

CFile: fix null pointer dereference
File: declare and implement class auto_buffer
File: replace CAutoBuffer usage with auto_buffer, fixes memory allocation check
File: add 'LoadFile' function and copy code from FileUtils
CFile::LoadFile: replace ugly reference to pointer with auto_buffer