Provide secure way of testing

[Nopik]

Currently there is quite a logic trying to figure out the incoming data. So, if one calls validate() without :json => true, and incoming data is not in valid format, validator tries very much to match the data. And does to e.g. by opening files from local hard drive.

If that is not desired, the only way to prevent such behavior is to call :json => true, which, unfortunately means, that in-memory structures need to be serialized to json first.

So, if I have some object of unknown type (which my happen to be "/etc/passwd" string), and I want to securely test it, currently I need to convert it to json, and json-parse it again in validator.

I'd like to have 'dumb' validate method, which do not have any fallbacks, if object does not match, it does not match, do not fallback. I.e. in https://github.com/hoxworth/json-schema/blob/master/lib/json-schema/validator.rb#L629 just be

elsif data.is_a?(String) && @options[ :literal_strings ] != true

kind of option.

[pd]

A lot of discussion is happening around this feature; see #148. I'm going to close this just to try to keep discussion centralized. Feel free to chime in. =)