BUG - `EvaluateRetrieval`'s `evaluate` doesn't consider results dict order

[vd-omermazig]

I'm guessing it because it runs C code underneath, and in the translation to HashMap the iteration order because the lexical order of the keys instead of the original order of the dict.

I opened a pull request that fixes the issue:

#183

[thakur-nandan]

We do not need to order the dict to retrieve results, pytrec_eval can evaluate this automatically without ordering the dict.