Detects file deleted due to case mismatch

[Sellorio]

When configuring grunt-contrib-watch to watch a particular file, unrelated watches will trigger a "file deleted" event if the casing on the file name is incorrect.

E.g.
Watch on file "File.txt" will trigger if the actual file's name is "FIle.txt" (capital i).

I didn't test all the scenarios but I know the watch triggers the file deleted event when unrelated watches have events.