Update AnalyticsManager.cs

Added UserIP and QuotaUser optional fields for the request, per https://developers.google.com/analytics/devguides/reporting/realtime/v3/parameters in order to enable heavier users to avoid hitting the limit of 10 queries per second (QPS) per IP/user if the code is run from a centralised location (such as a web service/site, etc).
Merge pull request #3 from ginji/patch-1

Update AnalyticsManager.cs