Add changelog

Format is:

    # Version - YYYY/MM/DD
    ## Language
    ### Features
    ### Fixes

Sections should be added as they are needed, so releases don't end up
with empty headings.
Merge pull request #59 from ResourceDataInc/changelog

Add changelog
[skip ci] Add missing c# tests and tweak JSON egs

This introduces test failures for c# that still need to be resolved.
Improve C# IEnumerable implementation
Update IEnumerable return type for JObject values

Return a KeyValuePair<string,dynamic> so the key isn't lost.
Update changelog
Merge pull request #60 from ResourceDataInc/dot-net-ienumerable

Improve C# IEnumerable implementation
Bump cs to 1.1.0-alpha2
[skip ci] Add missing .rb tests and tweak JSON egs

This introduces test failures for ruby that still need to be
resolved.
Fix python key existence check test
Implement enumeration of centroid object
Ruby - add failing test for json object enumeration
Ruby - fix enumeration for json objects