Support $apply in RESTier

[chinadragon0515]

Validate $apply support in RESTier, and add related test cases, if no support, then figure out detail cause and issues.

[danroot]

I'd like to see this also. GroupBy and distinct would be nice to have. http://docs.oasis-open.org/odata/odata-data-aggregation-ext/v4.0/csprd02/odata-data-aggregation-ext-v4.0-csprd02.html#_Toc378326329

[chinadragon0515]

@danroot thanks. If you have other features request related to RESTier which are not supported in RESTier, you can open issue directly.

[VikingsFan]

Relative issue OData/WebApi#726

[chinadragon0515]

@VikingsFan Can this be closed? thanks

[chinadragon0515]

document is updated, just add support of $apply, close the issue.