RegExp: runtime check for UTF-8 support
RegExp: runtime check for Unicode properties support
Startup log: warn if PCRE built without UTF-8 support or without Unicode properties support
RegExp: use UTF-8 regexps (off by default)
RegExp: report UTF-8 specific errors
FileItemList: use UTF-8 regexps
CUtil: use UTF-8 regexps for CleanString and ExcludeFileOrFolder
ExternalPlayer::Process: use UTF-8 regexp
PlayerSelectionRule::GetPlayers: use UTF-8 regexp
StackDirectory: use UTF-8 regexp
VideoInfoScanner: use UTF-8 regexp
ScraperParser: use UTF-8 regexp
Merge pull request #3434 from Karlson2k/regexp_rework_02

RegExp rework - part 02