Transform Feedback and Sampler API Implemented

Implemented API functions related to creating,
binding, deleting or accessing the parameters
of Transform Feedback and Sampler objects.

Change-Id: I267605733758332439addd71c24f5f438d22ba46
Reviewed-on: https://swiftshader-review.googlesource.com/2814
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>