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
The formatting of this section makes it difficult to orientate in the text.

How about the following format? The text below the line is the formatted result as would be rendered in README.

---

#### Usage

Display full usage info:
```
node-debug --help -l
```

Set debug port of debugging process to `5859`
```
node-debug -p 5859 app
```