TimeGrain parameter not supported

When getting historical usage metrics, there looks to be a parameter named TimeGrain which controls granularity (e.g. &TimeGrain=PT1M). However, the Azure SDK does not seem to support this with its WebSiteGetHistoricalUsageMetricsParameters class. Seeing as how the code is auto-generated for the class, the changes I've made in this pull request may not be applicable, but perhaps it will serve as a bug notification for the code generation tool instead.

I also recently noticed that flipping TimeGrain to explicitly say "PT1M" no longer return values over a certain time frame, whereas using "PT1H" still works in retrieving metrics for the same time frame. Has support for by-the-minute polling been removed?