PVR: Resolve channel dummy in GUIWindowPVRTimerSettings

When using Backend channel number , use channel unique ID member instead channel number
PVR: Cosmetics in GUIWindowPVRTimerSettings
Defer demuxer pause until buffers full
changed: Make network buffer more flexible/configurable
changed: Move read cache logic from DVDPlayer to CFile
fixed: Tab -> space
[win32] PeripheralBusUSB::PerformDeviceScan: rename parameter for clarity
[win32] PeripheralBusUSB: declare constant values as "const"
Values not supposed to be changed is better to declare as "const" to allow compiler optimize better.
[win32] PeripheralBusUSB::PerformDeviceScan: check for real memory allocation
[win32] PeripheralBusUSB::PerformDeviceScan: add check for presence of PID and VID
[win32] PeripheralBusUSB::PerformDeviceScan: Cosmetics
[win32] PeripheralBusUSB::PerformDeviceScan: optimization
[win32] PeripheralBusUSB::PerformDeviceScan: skip device on error and get rest of the devices; plus small optimization
[win32] PeripheralBusUSB::PerformDeviceScan: Allow reuse of buffer
instead of multiple frees/mallocs
[win32] PeripheralBusUSB::PerformDeviceScan: add fast detection of HID devices
[win32] PeripheralBusUSB::PerformDeviceScan: use function designed for device ID extraction
CFile: fix null pointer dereference in Stat() and Write()
[vfs] CFile: add null pointers checks
[settings] fix dealdlock in SettingsManeger introduced in #3512

As sugested by Montellese, using a shared lock fixes the deadlock in
SettinsManeger.
Merge pull request #3558 from huceke/fixups

[settings] fix dealdlock in SettingsManeger introduced in #3512