Implemented configuration frame work

Added reading and writing machinery's configuration file.
The file machinery_config.rb contains the default values
used when no configuration file is present.

It would be clearer to not nest the conditionals in one line, but write them as

```ruby
if @config_table[key][:type] == :boolean
  return get(key) ? "on" : "off"
else
  return get(key)
end
```