Fix os.sleep.

physfs: File handle locking, so filehandles won't be closed when some function still needs them; os.mkdir and os.removeall

physfs: Rudamentary usage tracking to not break multiple threads trying to read a file.

Physfs backend optimization.

Added string character access by @bauen1.

Update VFS again.

Update VFS for fixes!

Replace custom unixtime() with os.time, since it is inbuilt and most likely returning the unix time.

Update VFS (again).

Another VFS update to fix vfs.copy (hopefully)

Update vfs.

VFS updates and vfs.searchpath fixes if it changes.

Finally fix travis build.

Update VFS; Make thread.new's result function behave like pcall.

Update VFS