Implemented version query and removed a few unnecessary
UNIMPLEMENTED) calls.

Change-Id: I29bb53a8f8083a1b6fb091916dd156f47aac920c
Reviewed-on: https://swiftshader-review.googlesource.com/4754Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>