CsvWriter optionally ommit unneeded comma at the end of every line

[btrappe]

Using CsvWriter added an empty column because to every value field always a comma was appended, also for the last column value. To avoid breaking changes, I added the parameter omitLastComma to CsvWriter.WriteRow function family.

[electricessence]

Thanks for the PR!
Lemme take a look and see if we can proceed. :)
Just a note, I think this doesn't follow the CSV standard, but I'm happy to accommodate.

[electricessence]

I like where this went. I've got some minor changes I'd like to make.
I'll pull down master and update shortly.

[electricessence]

3.4 released:
https://www.nuget.org/packages/Open.Text.CSV/3.4.0
I refactored and redid a few things, but the API signature you provided is the same except for the parameter names.