node: allow nextTick infinite recursion

Removing the depth counter while processing the nextTickQueue made it
possible to run out of memory if in an infinite recursive loop using
nextTick(). There was also an edge case where too many callbacks were
pushed onto the nextTickQueue, while not actually being recursive.

This is being done to prevent possible cryptic FATAL ERROR messages from
popping up, and issues being posted about them.
http: DELETE shouldn't default to chunked encoding
http: check existence of default request headers