Fix (complement) for array reversed problem

The function to_value should be fixed, otherwise arrays in json would appear
inverted in erlang (the problem https://github.com/justinkirby/json_rec/pull/7 
wasn't only related to proplists). Besides, the eunit test showing this 
problem was missing, and the record associated with it was using a 
N-tuple rather than a list. (N-tuple is an invalid datatype for mochijson2). 
I fixed the record definition and implemented the test.