Restructured configuration system

Configuration logic from node-debug.js moved to config.js
node-debug receive configuration from rc now
config uses yargs argv preprocessor now
Removed conversion part of config.js
Fixed hight priority of node-debug hardcoded defaults
Fixed default web host for node-debug
  (`127.0.0.1` instead of `localhost`)
Fixed null value of web host
  (default web host is empty string now)
Added script option
Added list of avaible options as default help info
I am not sure what is the point of this `--script` argument. Could you please explain why would anybody want to use it?

Also why `app --flag --option=2`? Does it mean `app --option=2` will not work?

`--script --option=2 app` is clearly inferior to `app --option=2`, so there is no point adding `--script` for this use case.

Persisting `--script` in `rc` file does not make much sense to me. I suppose one may save `--script` in `.node-inspectorrc` in the project directory to provide local default arguments, but then that can be solved using other means (e.g. creating an alias, or a .sh/.bat file), so there is no need to introduce additional complexity in Node Inspector.