Merge pull request #97 from millecker/feature/rbclassload2

Refactored CudaRuntime2
Fixing up last commit. Adding new test case. See below.

Now ~/.rootbeer/config needs a config setup like this:
gpu_0_reserve_mem=8048576
gpu_1_reserve_mem=8048576

We are aiming to support multiple GPUs now thanks to
Martin Illecker's changes.
LargeThreadIndexTest passes on the GPU but not the CPU.

m_result[i] is always zero on the CPU from within runtest