Ensure that object cloning works

[silug]

Previously copying a ComplianceEngine::Data object (with Marshal.dump and Marshal.load) worked, but at some point that changed. We need to

1. Make that (or something like that) work again
2. Add tests for this

[silug]

After some testing, it seems like calling clone on a ComplianceEngine::Data works well enough.

I'm going to leave this open until we verify.

[silug]

If we need to do a custom clone (or maybe intialize_copy) method, it looks like something like this should work:

copy = ComplianceEngine::Data.new(*self.data.map { |_,v| v[:loader] })
(self.context_variables + self.cache_variables).each do |var|
  value = self.instance_variable_get(var)
  next if value.nil?
  if value.is_a?(Hash)
    copy.instance_variable_set(var, Marshal.load(Marshal.dump(value)))
  else
    copy.instance_variable_set(var, value.dup)
  end
end
copy