filesystem: add COverrideFile and COverrideDirectory
filesystem: reduce code duplication in CBlurayFile, CMultiPathFile, CSpecialProtocolFile and CSpecialProtocolDirectory by deriving from COverrideFile/COverrideDirectory
[win32] update VS project files
[osx/ios/atv2] - sync xcode project
Merge pull request #5599 from Montellese/override_fs

filesystem: add COverrideFile/COverrideDirectory to reduce code duplication