Startup log: fix POSIX/LINUX, better report FFMpeg, cosmetics
Startup log: Split long log string, add special version build information
[win32] SysInfo: implement and use sysGetVersionExWByRef() to overcome Win8.1 limitation on getting real Windows version
SysInfo: add GetKernelName() function for all platforms
SysInfo: rename GetKernelVersion -> GetOsNameWithVersionInfo
SysInfo: add GetKernelVersionFull() and GetKernelVersion() functions for all platforms
[linux] SystemInfo.cpp: add local static helpers getValueFromOs_release() and getValueFromLsb_release()
SysInfo: add GetOsName() function for all platforms
SysInfo: add GetOsVersion() function for all platforms
SysInfo: add GetOsPrettyNameWithVersion() function for all platforms
SysInfo: add GetModelName() and GetManufacturerName() functions for all platforms (currently only Darwin, Win32 and Android return meaningful values)
Startup log: unify startup log strings for all platforms, log manufacturer and model name
SysInfo::GetUserAgent: included win32 refactored part, updated code to use new functions
Rename kernelVersion->osVersionInfo, SYSTEM_KERNEL_VERSION -> SYSTEM_OS_VERSION_INFO
Old name was incorrect as XBMC provide much more information than just kernel version
SystemInfo: cleanup: remove unused platform-specific, outdated functions and ancient declared-only functions
[win32] SysInfo::GetKernelBitness: update for Vista+ only code, refactoring
[win32] SysInfo::GetKernelCpuFamily: use GetNativeSystemInfo() instead of GetSystemInfo()
SysInfo::HasVideoToolBoxDecoder: small refactoring and unification
SysInfo::GetBuildTargetPlatformName: update platform names to match GetOsName() values
SysInfo: add GetBuildTargetPlatformVersionDecoded() and update GetBuildTargetPlatformVersion()