edge case where watch does not see a delete event.

[dominictarr]

watch misses a delete event if the file is created, but not changed.

touch hello
# wait for watch to see it.
rm hello
# watch won't emit a removed event..

however, watch does see this...

touch hello
date > hello
rm hello

it's just a problem with the logic in watch, but not fs.watchFile,
this will generate created, then a modified event

touch hello
rm hello
touch hello

PR forthcoming.