test_mode: don't expect timestamp and spinner

[augnustin]

I am writing integration tests.
It means I'm trying to send a form without previous page load.
Which means I don't have the hidden timestamp and spinner and the negative captcha becomes invalid.

Shouldn't we have in: https://github.com/subwindow/negative-captcha/blob/fadfdf44d92f8e750ac1fd4394e6e637f254b2e7/lib/negative_captcha.rb

    if opts[:params] && (opts[:params][:spinner] || opts[:params][:timestamp]) || @@test_mode

and the same in the process method?