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.

I don't think it's more robust, as it introduces the possibility for additional errors, e.g. the type not being consistent with the type of the default value, typos in the type specification, etc.

I also don't think it makes sense to have no default value. There always has to be a default value and explicitly stating it for each option is the most simple way to do that.