Fixes #39 (Node server automatically shutdown)

[alx741]

Node server now sends every output to a tmp file, so it does not
automatically shutdown.

[alx741]

Now the first :w triggers the node server and works flawlessly; no need to start the server in a separate terminal anymore

[jaxbot]

Ah, interesting. Never had this happen to me, but makes sense why it would. Would it be better to redirect into /dev/null, though? No sense in wasting IO operations on the debug output

[alx741]

Yeah, i first thought node's output will be useful to keep, but i was using browserlink these days and that output is indeed a waste.

[jaxbot]

Looks good, thank you! 👍