GitLab

* updated fwd v4r4 to use gridwise gemm
* updated gridwise gemm api calls in bwd-data v1r1 and v2r1

* enabled atomic add in tensor copy
* added gridwise GEMM
* added backward data conv using GEMM + atomic
* added backward data conv using GEMM, no atomic

Refactor, so can bring multi-index transformation and padding support into MIOpen

enable type conversion in ThreadwiseGenericTensorSliceCopy_v2r1 and BlockwiseGenericTensorSliceCopy_v2

done: explicitly separate offset component into compile-time, block-invariant and per-thread components. Experimenting

WIP: explicitly separate offset component into compile-time, block-invariant and per-thread components