[bluray][files] Add new BlurayFile.

@jmarshallnz for review. This simple wrapper fixes loading of files prefixed with the bluray protocol, e.g., fanart, edl files, etc.
Needs some love form non win32 devs if the addition is considered reasonable.
`StringUtils::StartsWith()`? 
Or `urlDec.compare(0, 3, "://', 3) == 0`?