* node debug localhost:5858 - connects to remote debugger
* node debug -p `pgrep node` - connects to running process
* Fixed double-run of debugger on SIGUSR1

Coerce fractional, negative and non-numeric length arguments to numbers.
Fractional numbers are rounded up, negative numbers and non-numeric values
are set to zero.

* remove useless clearline call at Interface start
* silence after .handleBreak()
* output '\b' if this.stdout is not a tty (debugger)
* add '\b' checks for clearline (test)

The current behaviour will silently ignore any parsing errors
that may occur when loading a package.json file. This makes
debugging errors in the package.json file very difficult.

This changes the behaviour that that errors opening and reading
the file package.json file continue to be ignored, but errors
in parsing will throw an exception.

* Don't buffer command, before it's execution (repl)
* `quit` command, custom streams for .start, stubbed out test, disable
  history repeation for non-tty (debugger)

[debugger] fix 'debug> connecting...', fixed autostart (XXX figure out why it wasn't working in some cases), fixed highlighting for first line of module's code

micro-refactor, use rli.output.write instead of rli.write ('line' event was emitted for those writes)

Problem was exposed in 12798c62.