Cublas demo

[biddisco]

Demonstrates how to mix calls to CUDA cublas with hpx futures

[hkaiser]

@biddisco Thanks a lot! Does this now work with Boost V1.63 as well?

Also, could you please configure clang-format such that it does not align assignments and variable declarations?

[biddisco]

I added an #ifdef xxx_CUDA_ALLOCATOR around all the code that used the cuda::allocator and replaced the allocation and parallel::copy with cudaMalloc and cudaMemcpy - this means we can use the c++ compiler and everything compiles fine with any boost etc. When using the allocator, I was not able to get the nvcc compiler to work and did not want to remove all lambdas, so currently it will only compile (for me) using the non allocator version. My collaborators assure me that they will never use the allocators/copy/compute/etc that hpx provides and just need a demo that shows how to mix cublas and futures.

[biddisco]

I "align assignments and variable declarations" by hand because I like it. Are you telling me to stop?

[hkaiser]

I "align assignments and variable declarations" by hand because I like it. Are you telling me to stop?

We don't align variables or assignments anywhere else. But we don't enforce any particular style, only encourage authors not to change formatting in existing files. We also encourage authors to keep formatting of changed lines in existing files consistent with the existing style.

[biddisco]

I have put the indentations/alignments I changed back the way they were.

[hkaiser]

LGTM, thanks!