Further expand EventEmitter to TCP and HTTP

Further expand EventEmitter to TCP and HTTP

The constructor for TCP servers can no longer take a connection handler for
purely technical reasons. (The constructor for EventEmitter is implemented
in C++ but addListener is in javascript, and I don't want to make too many
C++ -> Javascript references.) Thus I introduce new constructor methods to
ease the creation of the servers:

  node.tcp.createServer()
  node.http.createServer()

These work almost the same as the old constructors.

In general we're working towards a future where no constructors are
publicly exposed or take arguments.

The HTTP events like "on_uri" are not yet using the event interface.
onMessage still is a constructor - but this will change soon.