implement retry for doPost in case of a 502 status code
new release build
* UsageModel.cs:

* AccountModel.cs: typo

* EventModel.cs: fixed date & timezone support:
- convert ticks in epoch milliseconds
- extract timezone

* RetrievalModel.cs: fixed constructor so the schema is OK

* EventTracker.NET.dll: rebuild

* Test.cs: add some date & timezone tests
Merge pull request #1 from squidsolutions/master

bug fixes