Added tests against v4 of ServiceStack.Text to verify compatibility.
add missing ServiceStack.Text v4 files
remove unneeded unit tests
Updated notes about v4 support and JsConfig
clarified language about v3 and v4 support.
update nuget.exe and use explicit -path switch on mkdir command.
Merge branch 'master' of github.com:AnthonyCarl/NodaTime.Serialization.ServiceStackText