Move VirtualDiscFileSystem to its own file.
Minor simplification to virtfs savestate.
Consider F:\ a valid recent iso.

File::Exists didn't like it, since it turned it into "F:".
Fix a potential crash in localtime_r win32.

Using localtime_s anyway.  Both ways it was actually threadsafe.
List directories in virtfs too.

Well, basically the same as directory, just skipping `.` and `..`...
Add .ppsspp-index.ini for virtfs dirs, for LBAs.

This way games that hardcode lbns in a file or elf can still be used.
Fix issues
Merge pull request #2 from Kingcom/virtfs

Fix issues in virtual disc filesystem.
Add basic infrastructure for file handler plugins.

The purpose of this is for games which use archive file formats
(containing many individual files), so that assets, files, etc. can be
worked on more rapidly.
Implement virtfs file handlers.
Oops, typo.
Implement a stub for handlers in GetFileInfo().
Switch to .lst instead of .ini.
Add a param to log filenames in virtfs handlers.
Improve performance of File::GetSize().
Merge pull request #2967 from unknownbrackets/virtfs

Implement plugin handlers for VirtualDiscFileSystem + fixes