Add new methods, new inputs, documentation and tests.

[DavideGCosta]

I tried to think as a student to figure out the easiest way to use this library.

You can see that I changed the output of the functions to avoid using repetition. Example: To get observations, we would do: x.Fred.Series.Observations.Observations, I think this might confuse students.

Also, in this case, I thought, what do we really want from this function (the data and the value), so despite saying that getting the JSON values is interesting, I think that having so many fields might be tricky for students. So I did:

|> Seq.map(fun obs -> 
    {
        Date = obs.Date
        Value = obs.Value
      })

If you want to see these changes to the different functions, use control + F with - Davide Costa to find the comments.

[nhirschey]

Should we close this now @DavideGCosta ?

[DavideGCosta]

Yes, I can see the changes! Will keep them in mind for next time! Yes, we can close it