Review comments incorporated

Hi Keith,

List of review comments incorporated

- [x] 1. GroupSummaryData parameter is named groupSummaryData, would it be better as summary or groupSummary
- [x] 3. You have two items for represent GroupLevel information a Long named groupLevel and GroupLevelData named 				groupLevelData, the groupLevelData one should be enough name groupLevel 
- [x] POST /groups with empty request still results in exception. 
		this was my silly, I was always referring Client code and thinking how ClientCreate code is handling this and thought may be based on Table definition ex. not null it automatically handle those situation. Looks like even Client create code need correction.
- [x] GET /groups?fields=id Should be able to return partial response as I require using fields=xxx approach, a number of fields however are not added as part of support data parameters for response. Where I should only see id I see the following:

Thanks
Nayan Ambali