showing breaking_changes on nuget update

[MehdiK]

See #103 for more details.

Need to verify whether this works or not and fix it if needed.

[robdmoore]

This definitely isn't there. I just checked the .nuspec. I must have been confused with the other libraries that I've done this for.

What we did with ChameleonForms the other day was add a readme.txt that links off the everything that the user might want to see (including breaking changes):

https://github.com/MRCollective/ChameleonForms/blob/master/ChameleonForms/ChameleonForms.nuspec#L45
https://github.com/MRCollective/ChameleonForms/blob/master/ChameleonForms/readme.txt

I suggest we do something similar.